EUROSEAS LTD.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13A-16 OR 15D-16 OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2026

Commission File Number:001-33283

EUROSEAS LTD.

(Translation of registrant’s name into English)

4 Messogiou & Evropis Street

151 24 Maroussi, Greece

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

INFORMATION CONTAINED IN THIS FORM 6-K REPORT

Attached hereto as Exhibit 1 is Management's Discussion and Analysis of Financial Condition and Results of Operations and unaudited interim condensed consolidated financial statements of Euroseas Ltd. and its subsidiaries (the "Company") as of and for the six-month period ended June 30, 2026. Also attached hereto as Exhibit 101 is the Interactive Data file relating to the materials in this Report on Form 6-K, formatted in Inline Extensible Business Reporting Language (iXBRL).

This Report on Form 6-K is hereby incorporated by reference into the Company's Registration Statements on Form F-3 (File No. 333-268708 & File No. 333-299121) filed with the Commission on December 7, 2022 and September 24, 2026, respectively.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF

FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following is a discussion of our financial condition and results of operations for the six months ended June 30, 2026. Unless otherwise specified herein, references to "we", "us”, "our”, "Euroseas", "Euroseas Ltd." or " the Company" shall include Euroseas Ltd. and its subsidiaries. You should read the following discussion and analysis together with the unaudited interim condensed consolidated financial statements and related notes included elsewhere in this report. For additional information relating to our management's discussion and analysis of financial condition and results of operations, please see our annual report on Form 20-F for the year ended December 31, 2025 filed with the U.S. Securities and Exchange Commission on April 29, 2026.

SELECTED CONSOLIDATED FINANCIAL DATA

The following table presents the Company’s selected consolidated financial and other data for each of the six-month periods ended June 30, 2025 and 2026, and as of December 31, 2025 and June 30, 2026. The selected consolidated statement of comprehensive income, cash flow and balance sheet data is derived from, and is qualified by reference to, our unaudited financial results for the six-month periods ended June 30, 2025 and 2026.

Euroseas Ltd. –Summary of Selected Historical Financials

(1) For the definition of calendar days, available days, voyage days and fleet utilization rate see our annual report on Form 20-F for the year ended December 31, 2025 (“Item 5A-Operating Results.”) filed on April 29, 2026.

(2) Average time charter equivalent rate, or average TCE, is a metric of the average daily net revenue performance of our vessels and is determined by dividing time charter revenue and voyage charter revenue, if any, gross of commissions, net of voyage expenses, or time charter equivalent revenues, or TCE revenues, by the number of voyage days during the relevant time period. Voyage expenses primarily consist of port, canal and fuel costs that are unique to a particular voyage, which would otherwise be paid by the charterer under a time charter contract, are related to repositioning the vessel for the next charter or incurred when a vessel is off hire/idle. Average TCE, a non-GAAP metric, provides additional meaningful information in conjunction with time charter revenue and voyage charter revenue, if any, the most directly comparable GAAP measure, because it assists our management in making decisions regarding the deployment and use of our vessels and because we believe it provides useful information to investors regarding our financial performance. Average TCE is a standard shipping industry performance metric used primarily to compare period-to-period changes in a shipping company's performance despite changes in the mix of charter types (i.e., spot voyage charters, time charters, pool agreements and bareboat charters) under which the vessels may be employed between the periods (see also “Item 5A-Operating Results” in our annual report on Form 20-F for the year ended December 31, 2025). Our definition of average TCE may not be comparable to that used by other companies in the shipping industry.

(3) We calculate daily total vessel operating expenses excluding drydocking expenses by dividing total vessel operating expenses excluding drydocking expenses for the relevant period by calendar days for such period. We calculate total vessel operating expenses as the sum of vessel operating expenses, related party management fees and general and administrative expenses. This metric assists our management and investors by increasing the comparability of our performance from period to period. Drydocking expenses include costs of shipyard, paints and agent expenses, which costs may vary from period to period.

The following table reflects the reconciliation of TCE revenues to time charter revenue and voyage charter revenue, if any, as reflected in the unaudited condensed consolidated statements of comprehensive income and our calculation of average TCE for the periods presented.

Six months ended June 30, 2026, compared to six months ended June 30, 2025.

Time charter revenue. Time charter revenue for the six-month period ended June 30, 2026, was $115.6 million, decreased compared to the same period in 2025 during which time charter revenue amounted to $116.8 million. The decrease in time charter revenue was mainly due to the decreased average number of vessels operating in the first six months of 2026 compared to the same period of 2025. While employed, our vessels generated an average TCE rate of $30,330 per day per vessel in the first six months of 2026, compared to $28,468 per day per vessel for the same period in 2025 (see calculation in the table above). An average of 21.0 vessels operated in the six months of 2026 for a total of 3,801 calendar days as compared to an average of 22.83 vessels during the same period in 2025 or 4,133 calendar days, an 8.0% decrease in terms of calendar days. Our voyage days, reflecting the number of days our fleet earned revenue, decreased by 7.0% to 3,799.6 days in the first six months of 2026 from 4,085.3 days in the same period in 2025. During the first six months of 2026, we had nil scheduled off-hire days, nil commercial off-hire days and 1.4 operational off-hire days compared to 29.8 scheduled off-hire days, nil commercial off-hire and 17.9 operational off-hire days in the first six months of 2025.

Commissions. Commissions for the six-month period ended June 30, 2026, amounted to $3.3 million, at 2.8% of time charter revenues, as compared to $3.2 million for the same period of 2025. The percentage of commissions over revenues was the same in the six-month period of 2026 compared to the same period of 2025. The overall level of commissions depends on the agreed commission for each charter contract.

Voyage expenses. Voyage expenses for the six-month period ended June 30, 2026, were $0.4 million compared to $0.5 million for the same period of 2025. Voyage expenses for the six-month periods ended June 30, 2026 and 2025 related to expenses for repositioning of our vessels between time charters and owners’ expenses at certain ports. Voyage expenses depend on the number of days our vessels are sailing for repositioning and any port or other costs incurred without a contract. During the six-month periods ended June 30, 2025 and 2026 the Company’s vessels were employed exclusively under time charter agreements. Voyage expenses usually represent a small fraction (0.4% and 0.3% in each of the first six months of 2025 and 2026) of charter revenues.

Vessel operating expenses. Vessel operating expenses were $22.9 million during the first six months of 2026, compared to $23.7 million for the same period of 2025. Daily vessel operating expenses increased between the two periods to $6,013 per day per vessel in the first six months of 2026 compared to $5,742 per day during the same period of 2025, a 4.7% increase mainly attributable to increased cost in vessel supplies during the period, because of the war in Middle East region.

Drydocking expenses. These are expenses we pay for our vessels to complete a drydocking as part of an intermediate or special survey or, in some cases, an in-water survey in lieu of a drydocking. The cost of passing a survey increases significantly if a dry-docking is required and depends on the extent of work that needs to be performed (such as amount of steel replacement required), the location of the drydock yard and whether it is an intermediate or a special survey with the latter almost always requiring a drydocking and more extensive work. In the first six months of 2025, three of our vessels completed extensive repairs afloat for a total cost of approximately $3.5 million. During the first six months of 2026, none of our vessels were drydocked. The total drydock cost for the period of $0.3 million relates to supplies performed for upcoming drydocks.

Vessel depreciation. Vessel depreciation for the six-month period ended June 30, 2026, was $13.4 million. Comparatively, vessel depreciation for the six-month period ended June 30, 2025 amounted to $15.3 million. This decrease was due to the lower average number of vessels owned in the first six months of 2026 compared to the same period of 2025.

Related party management fees. These are part of the fees we pay to Eurobulk Ltd. (“Eurobulk” or the “Manager”) under our Master Management Agreement. During the first six months of 2026, Eurobulk charged us 875 Euros per day per vessel totaling $4.0 million for the period, or $1,040 per day per vessel. In the same period of 2025, management fees amounted to $3.9 million, or $946 per day per vessel based on the daily rate per vessel of 840 Euros. Despite the lower number of vessels in our fleet, the increase in the total management fees is primarily due to the adjustment for inflation in the daily vessel management fee, effective from January 1, 2026, increasing it from 840 Euros to 875 Euros, as well as due to the unfavorable movement of the euro/dollar exchange rate.

Other operating (income)/expenses. During the six-month period ended June 30, 2025, other operating income amounted to $0.12 million, relating to loss of hire insurance received for one of our vessels. Other operating expenses of $0.44 million recognized in the first half of 2026 refers to expenses amounting to $0.6 million incurred for the formation of a partnership of the Company with a group of investors represented by NRP Project Finance AS (“NRP Investors”) of $0.60 million, whereby NRP Investors acquired a non-controlling interest of 49% ownership in the respective limited partnership entity Thrylos Containers LP (owner of M/V Thrylos), with the Company holding the remaining 51% controlling interest. The above-mentioned expenses were partly offset by an operating income from a settlement and closure of a claim with a charterer of $0.16 million.

General and administrative expenses. These expenses include the fixed portion of our management fees, incentive awards, legal and audit fees, directors’ and officers’ liability insurance, and other miscellaneous corporate expenses. In the first six months of 2026, we incurred a total of $3.5 million of general and administrative expenses, as compared to $3.2 million for the same period of 2025. The increase in the general and administrative expenses is primarily due to increased professional fees and increased cost for our stock incentive plan.

*Gain on sale of vessel.*The results of the Company for the first half of 2025 include a $10.2 million gain on the sale of M/V “Diamantis” that was completed in January 2025. No such case existed in the first half of 2026.

Other expenses, net. This line includes Interest and other financing costs, Loss on derivative, net, Foreign exchange loss and Interest income, which are discussed below:

Interest and other financing costs. Total interest and other financing costs for the first half of 2026 amounted to $5.7 million. For the same period of 2025 interest and other financing costs were $7.9 million. Capitalized interest charged on the cost of our newbuilding program was $0.1 million for the first six months of 2025. This decrease is due to the decreased amount of average outstanding debt and the decreased benchmark rates of our loans in the current period compared to the same period of 2025. For the six-month period ended June 30, 2026, our weighted average outstanding debt was approximately $213 million compared to a weighted average outstanding debt of approximately $243 million for the six-month period ended June 30, 2025. The weighted average benchmark rate on our bank debt for the six-month period ended June 30, 2026 was 3.7%, while the weighted average margin over the benchmark rate was 2.0% for a total weighted average interest rate of 5.7% per annum as compared to a weighted average benchmark rate for the six month period ended June 30, 2025 of 4.4%, and a weighted average margin over the benchmark rate of 2.1% for a total weighted average interest rate of 6.5% per year.

Loss on derivative, net. For the six months ended June 30, 2025 the Company recognized a $0.1 million realized gain and a $0.3 million unrealized loss for a total of $0.2 million net loss on its interest rate swap contract. The specific contract was closed within the year 2025 and no such case existed in the first half of 2026.

Loss on investments in equity securities and unrealized loss on investments in debt securities. For the first half of 2026, the Company recognized a $0.1 million unrealized loss on its investments in equity securities. This was the result of an investment in equity securities with an initial cost of $20.0 million acquired in the first quarter of 2026 and fair valued at $19.9 million as of the end of the second quarter of 2026. This investment was made as part of the Company’s short-term cash and liquidity management strategy, in the context of which the Company also acquired debt securities of initial cost of $20.0 million and fair valued at $18.9 million as of June 30, 2026, classified as available-for-sale under US GAAP, for which an unrealized loss of $1.1 million was recorded in “Other comprehensive loss” for the period. None of these investments existed in the second quarter of 2025.

Interest income. Interest income amounted to $3.2 million for the first six months of 2026 compared to $1.1 million interest income for the same period in 2025, mainly as a result of the higher amounts of our fixed deposits and the realized coupons from investments in debt securities.

Net income. As a result of the above, net income for the six months ended June 30, 2026 amounted to $65.1 million compared to a net income of $66.8 million for the same period in 2025.

Net loss attributable to non-controlling interest. As a result of the 49% ownership of the entity owning the M/V “Thrylos” represented by NRP investors, we recorded a net loss attributable to the non-controlling interest for the six months ended June 30, 2026, of $0.6 million. The amount was fully allocated to and reduced the non-controlling interest.

Net income attributable to controlling shareholders. As a result of the above, net income attributable to controlling shareholders for the six-month period ended June 30, 2026 was $65.7 million, as compared to a net income attributable to controlling shareholders of $66.8 million for the six-month period ended June 30, 2025.

Total comprehensive income. After deducting the unrealized loss of $1.1 million in equity securities recorded in “Other comprehensive loss” for the period, the total comprehensive income for the six-month period ended June 30, 2026 was $64.1 million, as compared to total comprehensive income of $66.8 million for the six-month period ended June 30, 2025.

Liquidity and capital resources

Historically, our sources of funds have been equity provided by our shareholders, operating cash flows, long-term borrowings and proceeds from vessel sales. Our principal use of funds has been capital expenditures to establish and expand our fleet, maintain the quality of our vessels during operations and the periodically required drydockings, comply with international shipping standards and environmental laws and regulations, fund working capital requirements and, if necessary, operating shortfalls, make principal repayments on outstanding loan facilities, and pay dividends.

Our short-term liquidity requirements include paying operating expenses, funding working capital requirements, interest and short-term principal payments on outstanding debt and the equity portion of our newbuilding vessel installments, repurchasing common shares under our share repurchase program and maintaining cash reserves to strengthen our position against adverse fluctuations in operating cash flows. Our primary sources of short-term liquidity is cash generated from operating activities, available cash balances and portions from debt and equity financings.

Our long-term liquidity requirements are funding the equity portion of vessel acquisitions and newbuilding vessel installments, debt repayment and payment of cash dividends when declared. Sources of funding for our long-term liquidity requirements include cash flows from operations, bank borrowings, issuance of debt and equity securities, and vessel sales.

Our total cash and cash equivalents and restricted cash at June 30, 2026, were $164.3 million, a decrease of $19.0 million from $183.3 million at December 31, 2025. We hold cash and cash equivalents primarily in U.S. Dollars, with a minor balance held in Euros. We conduct our funding and treasury activities based on corporate policies designed to minimize borrowing costs and maximize investment returns while maintaining the safety of the funds and appropriate levels of liquidity for our purposes.

OnJune 28, 2024, the Company signedtwo contracts for the construction oftwo eco-design fuel efficient containerships. The vessels will have a carrying capacity of4,484 teu each and will be built at Jiangsu Yangzi Xinfu Shipbuilding CO., Ltd., in China. Thetwo newbuildings are scheduled to be delivered in the third and the fourth quarter of2027. The total contracted consideration for thesetwo newbuilding contracts is approximately $120.5 million. As of June 30, 2026, the Company has paid $18.1 million, related to shipyard installments for the construction of thesetwo vessels.

On June 28, 2024, two subsidiaries, which were consolidated by the Company on July 28, 2025, entered into two contracts for the construction of two additional eco-design fuel-efficient containerships. The vessels will have a carrying capacity of4,484 teu each and will be built at Jiangsu Yangzi Xinfu Shipbuilding CO., Ltd., in China. Thetwo newbuildings are scheduled to be delivered in the first and second quarter of 2028 for a total cost of approximately $118.5 million. As of June 30, 2026, the Company has paid $17.8 million, related to shipyard installments for the construction of thesetwo vessels.

On December 16, 2025, the Company signed two contracts for the construction of two additional eco-design fuel efficient containerships. The vessels will have a carrying capacity of about2,800 teu each and will be built at Huanghai Shipbuilding Co., Ltd., in China. Thetwo newbuildings are scheduled to be delivered in the second and third quarter of 2028 for a total cost of approximately $92.7 million. As of June 30, 2026, the Company has paid $9.3 million, related to shipyard installments for the construction of thesetwo vessels.

On April 3, 2026, the Company signed two contracts for the construction of two additional eco-design fuel efficient containerships. The vessels will have a carrying capacity of about1,800 teu each and will be built at Nantong CIMC Sinopacific Offshore & Engineering Co., Ltd., in China. Thetwo newbuildings are scheduled to be delivered in the second and third quarter of 2028 for a total cost of approximately $64.5 million. As of June 30, 2026, the Company has paid $9.7 million, related to shipyard installments for the construction of thesetwo vessels.

On April 15, 2026, the Company signed two contracts for the construction of two additional eco-design fuel efficient containerships at Huanghai Shipbuilding Co., Ltd, in China exercising its option to expand the order placed on December 15, 2025. The vessels will have a carrying capacity of about2,800 teu. Thetwo newbuildings are scheduled to be delivered in the fourth of 2028 and the first quarter of 2029 for a total cost of approximately $92.7 million that will be gradually paid until the vessels’ delivery. As of June 30, 2026, the Company has paid $9.3 million, related to shipyard installments for the construction of thesetwo vessels.

On May 21, 2026, the Company signed two contracts for the construction of two additional eco-design fuel efficient containerships. The vessels will have a carrying capacity of about1,800 teu each and will be built at Nantong CIMC Sinopacific Offshore & Engineering Co., Ltd., in China. Thetwo newbuildings are scheduled to be delivered in the fourth of 2028 and the first quarter of 2029 for a total cost of approximately $64.5 million that will be gradually paid until the vessels’ delivery. As of June 30, 2026, the Company has paid $9.7 million, related to shipyard installments for the construction of thesetwo vessels.

As of June 30, 2026, an amount of approximately $479.7 million is payable to the shipbuilding yards for the twelve newbuilding vessels mentioned above, $54.5 million of which is due in the period ending June 30, 2027, $269.6 million is due in the period ending June 30, 2028 and $155.6 million is due in the period ending June 30, 2029.

All the payments are guaranteed by the Company. The Company intends to finance the cost of all the abovementioned newbuilding contracts with a combination of own cash and debt.

We believe that our current cash balance and our operating cash flows to be generated over the short-term period will be sufficient to meet our known short-term and long-term liquidity needs, including funding the operations of our fleet, capital expenditure requirements and any other present financial requirements.

Cash Flows

As of June 30, 2026, we had a working capital surplus of $179.4 million. For the six-month period ended June 30, 2026, we reported a net income of $65.1 million and a net income attributable to controlling shareholders of $65.7 million and we generated net cash from operating activities of $75.2 million. Our cash balance amounted to $157.4 million and cash in restricted and retention accounts amounted to $7.0 million as of June 30, 2026.

Net cash from operating activities.

Net cash provided by operating activities increased to $75.2 million for the six-month period ended June 30, 2026, from $68.5 million for the six-month period ended June 30, 2025. The major driver of the change of cash flows from operating activities for the period ended June 30, 2026 compared to the period ended June 30, 2025 is the increase in our net income (excluding non-cash items) of $80.4 million for the period ended June 30, 2026 compared to a net income (excluding non-cash items) of $71.0 million for the corresponding period in 2025 mainly driven by the decrease in dry-docking expenses and interest expense and the increase in interest income for the reasons explained further above.

Net cash from investing activities.

Net cash flows used in investing activities were $78.6 million for the period ended June 30, 2026, compared to $39.2 million for the same period of 2025. The net increase in cash flows used in investing activities of $39.4 million in the six month period ended June 30, 2026 compared to the six-month period ended June 30, 2025, is mainly attributable to a decrease of $12.9 million in the proceeds from vessel sales, a $5.0 million decrease in the advances received from a vessel held for sale, an increase of $0.2 million in the cash paid for vessel improvements and an increase of $40.0 million to the cash invested in equity and debt securities counterbalanced by a decrease of $18.7 million in payments related to vessels under construction.

Net cash from financing activities.

Net cash flows used in financing activities were $15.7 million for the six months ended June 30, 2026, compared to cash flows provided by financing activities of $2.7 million for the six months ended June 30, 2025. The net decrease in cash flows provided by financing activities of $18.4 million in the six month period ended June 30, 2026 compared to the six-month period ended June 30, 2025, is mainly attributable to the following: a decrease by $51.6 million in loan proceeds, net of loan arrangement fees paid and the increase in the dividends paid by $6.3 million counterbalanced by a decrease by $19.4 million in debt principal payments, an increase by $5.6 million in contributions by non-controlling shareholders and a decrease in cash paid for share repurchase by $1.3 million.

Debt Financing

We operate in a capital-intensive industry, which requires significant amounts of investment, and we fund a portion of this investment through long-term debt. We target debt levels we consider prudent at the time of conclusion of such debt funding based on our market expectations, cash flow, interest coverage and percentage of debt to capital amongst other factors.

As of June 30, 2026, we had seven outstanding bank loans and one sale and lease back financing transaction with a combined outstanding balance of $208.1 million. These loans mature between 2027 and 2034. Our long-term debt as of June 30, 2026 comprises debt granted to our vessel-owning subsidiaries with margins over SOFR ranging from 1.80% to 2.295%. A description of our loans as of June 30, 2026, is provided in Note 7 of our attached unaudited interim condensed consolidated financial statements. As of June 30, 2026, we are scheduled to repay approximately $18.1 million of the above debt in the following twelve months.

Recent Developments

Please refer to Note 16 to our unaudited interim condensed consolidated financial statements, included elsewhere herein, for developments that took place after June 30, 2026.

Unaudited Interim Condensed Consolidated Financial Statements

Index to unaudited interim condensed consolidated financial statements