You can write off a boat as a second home and deduct the loan interest, but only if the vessel has sleeping quarters, a toilet, and cooking facilities, the loan is secured by the boat, and your total itemized deductions exceed the standard deduction. That last piece is where most boat owners lose the benefit: for 2026, itemized deductions have to clear $32,200 for a married couple filing jointly or $16,100 for a single filer before any of this interest saves you a dollar.
The Three Features Your Boat Must Have
The IRS treats a qualifying boat as a “dwelling unit,” the same category it uses for houses, condos, and mobile homes. To count, the vessel needs basic living accommodations: sleeping space, a toilet, and cooking facilities. All three. A center-console fishing boat with a cooler and a bench seat does not qualify no matter what it cost.
Sleeping space means a berth, bunk, or cabin area intended for overnight use. The toilet can be a portable marine head or a built-in system. Cooking facilities are the murkiest requirement. IRS Publication 936 uses the phrase “sleeping, cooking, and toilet facilities” without further definition. A permanently installed cooktop with counter space and a sink makes the strongest case. A standalone microwave on a shelf is a gray area that could invite questions in an audit.
Most cabin cruisers, trawlers, and sailboats 25 feet and longer meet all three requirements from the factory. If you’re buying with the tax treatment in mind, confirm the layout before you sign.
How Much Interest You Can Actually Deduct
Interest on a qualifying boat loan follows the same rules as a home mortgage. You can deduct interest on up to $750,000 of combined debt across your primary home and the boat if you’re married filing jointly, or $375,000 if you file separately. Legislation enacted in 2025 made this limit permanent.
Only “acquisition indebtedness” qualifies. The loan proceeds must have gone toward buying or substantially improving the boat. If you refinance and pull cash out for something unrelated to the vessel, interest on that extra amount is not deductible. The old home equity interest deduction that once allowed this was eliminated, and that change is now permanent too.
Consider the math on a stacked balance. If you already carry a $600,000 mortgage on your house and finance a boat for $250,000, your combined debt is $850,000. Interest attributable to the last $100,000 produces no federal tax benefit because you’re over the cap.
The loan also has to be secured by the boat. For vessels documented with the U.S. Coast Guard, that usually means a preferred ship mortgage filed with the Coast Guard’s documentation center. For state-registered boats, lenders 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 checklist.
Why the Standard Deduction Blocks Most Buyers
This 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 clear those numbers, the boat’s second-home status delivers nothing.
Run the numbers on a typical buyer. Finance a $150,000 boat at 7% and you’ll pay roughly $10,500 in interest the first year. Add $6,000 in property tax on the primary home and a few thousand in charitable giving, and a married couple is still under $32,200 in itemized deductions. The deduction exists on paper and saves them nothing.
The owners who actually benefit are the ones already itemizing for other reasons: a sizable mortgage on the primary home, heavy state income taxes, or substantial charitable giving. The boat interest then stacks on top of deductions already past the standard-deduction threshold.
Claiming the Deduction Without a Form 1098
Homeowners expect a Form 1098 every January showing mortgage interest paid. Boat owners usually won’t 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 directly, 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.
Report the interest on Schedule A, line 8b, the line for deductible mortgage interest not reported on Form 1098. You’ll need the lender’s name, address, and taxpayer identification number, plus the total interest you paid for the year. Keep your loan statements. If the IRS questions the entry, those statements are your proof.
What Happens If You Rent the Boat Out
Never renting the boat keeps things simple: it qualifies as a second residence regardless of how many days you use it. Renting at fair market value changes the analysis.
Once you rent, you have to personally use the boat for the greater of 14 days or 10% of the days it’s rented at a fair price. Miss that threshold and the IRS treats the boat as a rental property. The interest expense then falls under the passive activity loss rules, which generally prevent you from deducting rental losses against your salary or other active income. The tax benefit largely disappears.
The cleanest scenario for occasional renters is keeping rental days to 14 or fewer for the entire year. Under that rule, the rental income is tax-free and doesn’t even go on your return, and you still claim the full mortgage interest deduction as though the boat were never rented.
One helpful detail sits inside Publication 527: days spent substantially full time on maintenance and repairs do not count as personal-use days, even if family members are aboard recreating while you work. Log every day the boat is used, by whom, and for what purpose. In an audit, you carry the burden of proving you met the personal-use threshold.
Property Tax on the Boat
Some states impose an annual personal property tax on boats based on value. Where that tax exists, it’s 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 beginning once modified adjusted gross income exceeds roughly $500,000. The cap cannot drop below $10,000 even at the highest income levels.
Whether the boat’s property tax adds any real benefit depends on where you already stand. If state income taxes and real property taxes on your home already consume most of the SALT cap, the boat tax gives you little more. That’s common for owners in high-tax states already at the ceiling.
Chartering the Boat Is a Different Path
Running the boat as a charter operation puts you into business-deduction territory, not second-home territory, and you cannot claim both for the same periods. The IRS scrutinizes charter setups that look like personal boating with occasional paying passengers, and consistent losses with minimal bookings can be recharacterized as a hobby, in which case the losses aren’t deductible. If chartering is what you’re planning, treat it as a separate tax question from the second-home write-off.