Writing off a boat as a second home is allowed under federal tax law, and the mechanics mirror the mortgage interest deduction on a house. The vessel has to include sleeping space, a toilet, and cooking facilities; the loan has to be secured by the boat; and your itemized deductions have to beat the standard deduction, which is $32,200 for married couples filing jointly and $16,100 for single filers in 2026.1
The Three Features Your Boat Needs
The IRS treats a boat as a potential “dwelling unit” the same way it treats a house, condo, or mobile home. To count, the vessel must have basic living accommodations: sleeping space, a toilet, and cooking facilities. All three are required. A center-console fishing boat with a cooler and a bench seat will not qualify, no matter what it cost.
Sleeping space means a berth, bunk, or cabin area designed for overnight use. A toilet can be anything functional, from a portable marine head to a built-in electric system. Cooking facilities are where things get murkier. IRS Publication 936 uses the phrase “sleeping, cooking, and toilet facilities” without elaboration, and does not say whether a hot plate plugged into an outlet qualifies or whether you need a fixed galley with a stove. In practice, a permanently installed cooktop with a countertop and sink makes the strongest case. A standalone microwave sitting on a shelf is a gray area that could invite scrutiny during an audit.
Most cabin cruisers, trawlers, and sailboats 25 feet and longer satisfy all three requirements straight from the factory. If you are shopping with the tax benefit in mind, verify the layout before you buy.
How Much Interest Qualifies
Interest on a qualifying boat loan works under the same rules as a traditional mortgage. You can deduct interest on up to $750,000 of combined mortgage debt across your primary home and second home if you are married filing jointly, or $375,000 if you file separately. That limit was made permanent by legislation enacted in 2025.
Only “acquisition indebtedness” counts, meaning the loan was used to buy or substantially improve the boat. Refinance the boat loan and pull cash out for something unrelated, and the interest on that extra amount is not deductible. The older home equity interest deduction that once allowed this is gone, and that change is now permanent.
The math matters. If you already carry a $600,000 mortgage on your house and finance a boat for $250,000, your combined debt is $850,000. You can only deduct interest on the first $750,000, so the interest tied to the extra $100,000 generates no tax benefit.
The loan also has to be secured by the boat itself. For vessels documented with the U.S. Coast Guard, this is typically a preferred ship mortgage filed with the Coast Guard’s documentation center. For state-registered boats, lenders usually file a lien under state law. An unsecured personal loan used to buy a boat produces no deductible interest, even if the boat has every amenity on the list.
You Have To Itemize, and Most People Don’t
The mortgage interest deduction only helps taxpayers who itemize on Schedule A. For 2026 the standard deduction is $32,200 for married couples filing jointly and $16,100 for single filers. Unless your total itemized deductions, including boat loan interest, mortgage interest on your primary home, state and local taxes, and charitable contributions, clear that threshold, the boat’s second-home status is worth nothing on your return.
This is where the benefit sinks for a lot of buyers. Someone financing a $150,000 boat at 7% pays roughly $10,500 in interest the first year. Combine that with a $6,000 property tax bill on a primary home and a few thousand in charitable giving, and a married couple is still under $32,200 in itemized deductions. The boat interest deduction exists on paper and delivers zero actual savings.
Owners most likely to benefit are those who already itemize because of a large mortgage on their primary home, significant state income taxes, or substantial charitable giving. The boat loan interest then stacks on top of deductions that were already pushing them past the standard deduction.
Claiming the Deduction Without a Form 1098
Homeowners are used to receiving a Form 1098 each January showing the mortgage interest they paid. Boat owners usually will not get one. The IRS only requires lenders to file Form 1098 for loans secured by real property, and a boat is personal property. The Form 1098 instructions acknowledge this, noting that a borrower “may be entitled to a deduction for qualified residence interest, such as in the case of a loan for a boat” even when the lender has no filing obligation.
Without a Form 1098, report the deductible interest on Schedule A, line 8b, which is the line for deductible mortgage interest not reported on Form 1098. You will need the lender’s name, address, and taxpayer identification number, along with the total interest you paid during the year. Keep your loan statements. If the IRS questions the deduction, those statements are your proof.
What Happens If You Rent the Boat Out
If you never rent the boat out, it qualifies as a second residence regardless of how many days you actually use it. Renting changes the picture.
Once you rent the boat to others at fair market value, you must personally use it for the greater of 14 days or 10% of the days it is rented out. Fall short and the IRS reclassifies the boat as a rental property, which throws the interest into the passive activity loss rules. Those rules generally stop you from deducting rental losses against your salary or other active income, which guts the benefit.
The friendliest scenario for occasional renters is keeping rental to 14 days or fewer during the whole year. Under that rule, the rental income is completely tax-free and you do not even report it. You still claim the full mortgage interest deduction as though the boat were never rented.
Days you spend doing maintenance and repairs do not count as personal use days, a detail buried in IRS Publication 527. A full day cleaning the hull, servicing the engine, or replacing rigging stays out of your personal-use column, even if family members are aboard recreating while you work. The day has to be spent “substantially full time” on maintenance, not improvement, to qualify.
Keep a detailed log of every day the boat is used, by whom, and for what. In an audit, you carry the burden of proving you met the personal-use threshold, and vague recollections will not hold up.
One related boundary: if you run the boat as a charter business and try to deduct depreciation, fuel, insurance, and docking fees, that is a separate tax regime with its own rules on hobby losses and expense allocation. You cannot simultaneously treat the boat as a second home and deduct it as a business for the same periods.
Property Tax on the Boat
Some states impose an annual personal property tax on boats based on the vessel’s value. Where it exists, that tax is deductible on your federal return as part of the state and local tax (SALT) deduction. The SALT deduction is capped. For 2026 the cap is approximately $40,000 for most filers, with a phase-out that starts reducing the cap once modified adjusted gross income exceeds roughly $500,000. The cap cannot drop below $10,000 even at the highest income levels.
The practical impact depends on where you already sit with SALT. If your state income taxes and real property taxes on your home already consume most of your cap, the boat’s property tax adds little additional federal benefit. That is especially common for boat owners in high-tax states who are already bumping against the ceiling.