+Exhibit 99.1

CFSB BANCORP, INC. ANNOUNCES FISCAL THIRD QUARTER AND YEAR-TO-DATE 2025 FINANCIAL RESULTS

QUINCY, Massachusetts, April 29, 2025 – CFSB Bancorp, Inc. (the “Company”) (NASDAQ Capital Market: CFSB), the holding company for Colonial Federal Savings Bank (the “Bank”), today announced net income of $4,000, or $0.00 per basic and diluted share, for the three months ended March 31, 2025, a net loss of $162,000, or $0.03 per basic and diluted share, for the three months ended December 31, 2024, and a net loss of $40,000, or $0.01 per basic and diluted share, for the three months ended March 31, 2024.

For the nine months ended March 31, 2025, the Company recorded a net loss of $164,000, or $0.03 per basic and diluted share, compared to a net loss of $127,000, or $0.02 per basic and diluted share, for the nine months ended March 31, 2024.

Michael E. McFarland, President and Chief Executive Officer, states “Returns on interest-earning assets continue to show improvement. The costs of deposit liabilities are showing a slight decline as certificates of deposits continue to reprice downward into shorter term products. Loan growth and expense reduction continue to trend in positive directions. With the volatility of both the financial markets and economic conditions, we continue to remain optimistic."

Third Quarter Operating Results

Net interest income, on a fully tax-equivalent basis, increased by $65,000, or 3.8%, to $1.8 million for the three months ended March 31, 2025, from $1.7 million for the three months ended December 31, 2024. The net interest margin increased by seven basis points to 2.05% for the three months ended March 31, 2025, from 1.98% for the three months ended December 31, 2024. Interest income increased $3,000, or 0.1%, due to a $10,000 increase in interest and dividends on securities, and a $73,000 increase in interest and fees on loans, offset by an $80,000 decrease in interest on cash and short-term investments. Interest expense decreased $62,000, or 3.9%, to $1.5 million for the three months ended March 31, 2025, from $1.6 million for the three months ended December 31, 2024. The increase in net interest income was due to higher average yields on interest-earning assets as assets with lower rates are replaced with interest-earning assets with higher rates and a decrease in the cost of deposits.

Net interest income, on a fully tax-equivalent basis, increased by $110,000, or 6.6%, to $1.8 million for the three months ended March 31, 2025, from $1.7 million for the three months ended March 31, 2024. The net interest margin increased by nine basis points to 2.05% for the three months ended March 31, 2025, from 1.96% for the three months ended March 31, 2024. Interest income increased $254,000, or 8.4%, due to a $107,000 increase in interest and dividends on securities, an $86,000 increase in interest on cash and short-term investments and a $61,000 increase in interest and fees on loans. Interest expense increased $144,000, or 10.5%, to $1.5 million for the three months ended March 31, 2025, from $1.4 million for the three months ended March 31, 2024. The increase in net interest income was due to higher average yields on interest-earning assets as assets earning lower yields are replaced with interest-earning assets earning higher yields, offset by an increase in the average balance of and rate paid on certificates of deposit..

The Company recorded a provision for credit losses of $66,000 for the three months ended March 31, 2025 and reversals of the provision for $79,000 and $20,000, for the three months ended December 31, 2024 and March 31, 2024, respectively. The $5,000 reversal for credit losses for securities held to maturity was primarily due to improvements in economic conditions for the three months ended March 31, 2025. The $26,000 reversal of provision for credit losses for off-balance sheet exposures was primarily due to a decrease of $2.3 million in unfunded commitments at March 31, 2025. The $97,000 provision for credit losses for loans was primarily due to increases in loan originations during the three months ended March 31, 2025. The allowance for credit losses on loans as a percentage of total loans was 0.86%, 0.83%, and 0.91% at March 31, 2025, December 31, 2024, and March 31, 2024, respectively.

Non-interest income decreased $5,000, or 3.0%, to $160,000 for the three months ended March 31, 2025, from $165,000 for the three months ended December 31, 2024, primarily due to a decrease of $3,000 in income on bank-owned life insurance and a decrease of $3,000 in other income.

Non-interest income decreased $7,000, or 4.2%, to $160,000 for the three months ended March 31, 2025, from $167,000 for the three months ended March 31, 2024, primarily due to a decrease of $4,000 in customer service fees and $3,000 in other income.

Non-interest expense decreased $197,000, or 9.6%, to $1.8 million for the three months ended March 31, 2025, from $2.0 million for the three months ended December 31, 2024. The decrease was primarily due to a $180,000 decrease in salaries and employee benefit expense due to prior quarter employee merit salary and benefit increases, and a decrease of $28,000 in other general and administrative expenses, offset by a $20,000 increase in occupancy and equipment expense.

Non-interest expense decreased $61,000, or 3.2%, to $1.8 million for the three months ended March 31, 2025, from $1.9 million for the three months ended March 31, 2024. The decrease was primarily due to a $79,000 decrease in salaries and employee benefit expense, primarily due to a reduction in pension costs, offset by a $7,000 increase in other general and administrative expenses and a $6,000 increase in data processing costs.

The Company recorded a benefit for income tax of $3,000 for the three months ended March 31, 2025, compared to a provision for income taxes of $51,000 for the three months ended December 31, 2024. The decrease in the provision for income taxes for the three months ended March 31, 2025 was due to the change in the deferred tax and the deferred tax valuation allowance on the charitable contribution carryover.

The Company recorded a benefit for income tax of $3,000 for the three months ended March 31, 2025, compared to a benefit for income taxes of $42,000 for the three months ended March 31, 2024. The increase in the provision for income taxes for the three months ended March 31, 2025 was due to the change in the deferred tax and the deferred tax valuation allowance on the charitable contribution carryover.

Year-to-Date Operating Results

Net interest income, on a fully tax-equivalent basis, decreased by $13,000, or 0.3%, to $5.1 million for the nine months ended March 31, 2025, from $5.2 million for the nine months ended March 31, 2024. The net interest margin decreased by eight basis points to 1.99% for the nine months ended March 31, 2025, from 2.07% for the nine months ended March 31, 2024. Interest income increased $1.2 million, or 13.8%, due to a $664,000 increase in interest on cash and short-term investments, a $396,000 increase in interest and dividends on securities, and a $130,000 increase in interest and fees on loans. These changes reflect an increased yield on interest-earning assets of 33 basis points as interest-earning assets earning lower yields are replaced with interest-earning assets earning higher yields. The increase in interest income benefited from an increase in the average balance of cash and short-term investments of $18.8 million, partially offset by a decrease in the average balance of loans of $5.2 million and a decrease in the average balance of securities of $1.1 million. Interest expense increased $1.2 million, or 34.8%, due to an increase of $1.2 million in interest expense on interest-bearing deposits, and a $20,000 increase in interest expense on Federal Home Loan Bank ("FHLB") advances. The increase in interest expense on interest-bearing deposits reflected a 56 basis point increase in the average cost, primarily due to the higher interest rate environment and an increased percentage of higher cost certificates of deposit in the portfolio. The increase in interest expense on FHLB advances was due to a $1.7 million, or 19.3%, increase in the average balance of FHLB advances for the nine months ended March 31, 2025, offset by a 58 basis point decrease in the average cost of FHLB advances as newer advances were borrowed at lower rates.

The Company recorded a reversal of the provision for credit losses of $84,000 for the nine months ended March 31, 2025, compared to a reversal of the provision for credit losses of $290,000 for the nine months ended March 31, 2024. The $1,000 reversal of the provision of credit losses for off-balance sheet exposures was primarily due to a decrease of $315,000 in unfunded commitments at March 31, 2025. The $49,000 reversal of the provision for credit losses for loans recorded for the nine months ended March 31, 2025 reflected continued strong asset quality, improvements in forecasted economic conditions and lower loan balances. The $35,000 reversal of the provision for credit losses on securities held to maturity for the nine months ended March 31, 2025 was primarily due to improvements in economic conditions.

Non-interest income decreased $4,000, or 0.8%, to $495,000 for the nine months ended March 31, 2025 from $499,000 for the nine months ended March 31, 2024.

Non-interest expense decreased $171,000, or 2.9%, to $5.8 million for the nine months ended March 31, 2025 from $5.9 million for the nine months ended March 31, 2024. The decrease was due to a $176,000 decrease in salaries and employee benefit expense primarily

due to a reduction in pension costs and a $15,000 decrease in other general and administrative expenses, partially offset by an $18,000 increase in data processing costs.

The Company recorded a provision for income taxes of $67,000 for the nine months ended March 31, 2025 and 2024, respectively. The provision for income taxes for the nine months ended March 31, 2025 was due to the decrease in income before income taxes, offset by an increase in the deferred tax valuation allowance on the charitable contribution carryover. The deferred tax related to the charitable contribution carryover was reduced by a 100% valuation allowance because management believes that it is more likely than not that the benefit of these deferred tax assets will not be realized. The ultimate realization of these deferred tax assets is dependent upon the generation of future taxable income. The valuation allowance for these net deferred tax assets may be adjusted in the future if estimates of taxable income during the carryforward period are increased.

Balance Sheet

Assets: At March 31, 2025, total assets amounted to $366.2 million, compared to $363.4 million at June 30, 2024, an increase of $2.8 million, or 0.8%. The increase resulted primarily from an increase in cash and cash equivalents of $1.3 million, and an increase in total loans of $2.8 million, offset by a decrease in securities held to maturity of $1.1 million. The increase in cash and cash equivalents was primarily due to increases in deposits of $3.0 million and decreases in securities held to maturity of $1.1 million, offset by increases in loans of $2.8 million.

Asset Quality: At March 31, 2025, there were four one- to four-family loans totaling $1.4 million rated substandard with an allowance for credit loss of $10,000. These loans were rated substandard due to the borrowers' inability to show sufficient rent receipts to support the debt service coverage. There were no loans rated special mention, doubtful or loss at March 31, 2025. There were no charge-offs or recoveries during the nine months ended March 31, 2025.

Liabilities: At March 31, 2025, total liabilities amounted to $290.5 million, compared to $287.4 million at June 30, 2024, an increase of $3.1 million, or 1.1%. Deposits increased by $3.0 million, or 1.1%, to $273.8 million at March 31, 2025 compared to $270.8 million at June 30, 2024. The increase was primarily due to an increase of $5.8 million in higher-yielding term certificates of deposit, offset by a decrease of $1.4 million in non-interest-bearing and interest-bearing NOW and demand accounts and a decrease of $1.0 million in regular accounts. The change in composition and the increase in certificates of deposit was a result of the Bank offering certificate of deposit promotions as customers sought accounts with higher interest rates.

Stockholders' Equity. Total stockholders' equity decreased $335,000 to $75.7 million at March 31, 2025, from $76.1 million at June 30, 2024. The decrease was primarily due to the purchase of Company stock of $495,000 and the net loss for the nine months ended March 31, 2025 of $164,000, offset by the changes in unearned ESOP compensation of $77,000 and stock-based compensation expense of $269,000.

About CFSB Bancorp, Inc.

CFSB Bancorp, Inc. is the federal mid-tier holding company of Colonial Federal Savings Bank and is the majority-owned subsidiary of 15 Beach, MHC. Colonial Federal Savings Bank is a federally chartered stock savings bank that has served the banking needs of its customers on the south shore of Massachusetts since 1889. It operates from three full-service offices and one limited-service office in Quincy, Holbrook and Weymouth, Massachusetts.

Forward Looking Statements

This press release contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, which can be identified by the use of words such as “estimate,” “project,” “believe,” “intend,” “anticipate,” “assume,” “plan,” “seek,” “expect,” “will,” “may,” “should,” “indicate,” “would,” “contemplate,” “continue,” “target” and words of similar meaning. These forward-looking statements are based on our current beliefs and expectations and are inherently subject to significant business, economic and competitive uncertainties and contingencies, many of which are beyond our control. In addition, these forward-looking statements are subject to assumptions with respect to future business strategies and decisions that are subject to change. Certain factors that could cause actual results to differ materially from expected results include increased competitive pressures, demand for loan products, deposit flows, changes in the interest rate environment, the effects of inflation, general economic conditions (including potential recessionary conditions) or conditions within the securities markets, monetary and fiscal policies of the U.S. Government, including policies of the U.S. Treasury and the Board of Governors of the Federal Reserve Board; changes in the quality, size and composition of our loan and securities portfolios, changes in liquidity, including the size and composition of our deposit portfolio, and the percentage of uninsured deposits in the portfolio; changes in asset quality, prepayment speeds, charge-offs and/or credit loss provisions, our ability to access cost-effective funding; changes in demand for our products and services; legislative, accounting, tax and regulatory changes; the imposition of tariffs or other domestic or international governmental policies; the current or anticipated impact of military conflict, terrorism or other geopolitical events; a failure in or breach of our operational or security systems or infrastructure, including

cyberattacks that could adversely affect the Company’s financial condition and results of operations and the business in which the Company and the Bank are engaged, the failure to maintain current technologies and the failure to retain or attract employees.

You should not place undue reliance on forward-looking statements. CFSB Bancorp, Inc. undertakes no obligation to revise these forward-looking statements or to reflect events or circumstances after the date of this press release.

CFSB Bancorp, Inc. and Subsidiary

Consolidated Balance Sheets (Unaudited)

(In thousands, except per share data)

CFSB Bancorp, Inc. and Subsidiary

Consolidated Statements of Net (Loss) Income (Unaudited)

(In thousands, except per share data)

CFSB Bancorp, Inc. and Subsidiary

Average Balances and Yields, Fully Tax-Equivalent Basis (Unaudited)

(Dollars in thousands)

(1) Includes tax equivalent adjustments for municipal securities, based on a statutory tax rate of 21%, of $19,000, $19,000, and $24,000 for the three months ended March 31, 2025, December 31, 2024 and March 31, 2024, respectively.

(2) Net interest rate spread represents the difference between the weighted average yield earned on interest-earning assets and the weighted average rate paid on interest-bearing liabilities.

(3) Net interest-earning assets represent total interest-earning assets less total interest-bearing liabilities.

(4) Net interest margin represents net interest income divided by average total interest-earning assets.

(5) Cost of deposits represents the total interest paid on deposits, divided by total interest-bearing deposits plus total non-interest-bearing deposits.

(6) Cost of funds represents the total interest paid on liabilities, divided by total interest-bearing liabilities plus total non-interest-bearing deposits.

CFSB Bancorp, Inc. and Subsidiary

Reconciliation of Fully Tax-Equivalent Income

(Unaudited) (In thousands)

CFSB Bancorp, Inc. and Subsidiary

Average Balances and Yields, Fully Tax-Equivalent Basis (Unaudited)

(Dollars in thousands)