Last updated: August 20, 2026
Winterizing a pontoon is the same engine job as any other outboard boat plus two things a V-hull owner never thinks about: a huge deck of furniture that spends the winter absorbing whatever the weather does, and aluminum tubes that will hold the season’s waterline stain until you deal with it. Owners tend to nail the motor and lose the furniture.
There is also a covering problem that is specific to the shape. A pontoon deck is wide, flat and long, which is the worst possible geometry for shedding rain and snow. Without support underneath, a pontoon cover becomes a pool. This guide covers the toons, the furniture and the motor in the order that actually works.
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Quick Answer
How do you winterize a pontoon boat?
- Do the outboard first: treat the fuel, flush, fog per the manual, change gear oil, and store the leg tilted fully down.
- Clean the tubes before storage so a season of waterline stain does not sit on the aluminum for months.
- Strip the deck: cushions off or on edge, everything out of the storage compartments, bimini down and dry.
- Cover over a proper support system, because a flat pontoon deck pools water unless something forces a peak.
Bottom line: the motor steps match any outboard boat. The pontoon-specific work is the tubes, the furniture and the cover support.
What Makes a Pontoon Different
Three things. The deck is a flat, wide surface that cannot shed water on its own. The furniture is a large amount of marine vinyl over foam and plywood, all of which hates trapped damp. And the hull is aluminum tubing rather than gelcoat, so it stains and oxidizes rather than chalking, and it wants a different cleaner.
The engine, meanwhile, is usually a conventional outboard, so the mechanical side of the job is the same one every outboard owner does. If you are new to that part, the sequence is laid out in our full winterization checklist.
Start With the Motor
Add marine fuel stabilizer, run the engine on muffs so treated fuel reaches the carburetor or injectors, and flush the cooling passages with fresh water while it runs. Then fog the engine using the method in your manual, change the lower unit gear oil, change the engine oil and filter on a four-stroke, and grease the fittings.
Leave the outboard tilted fully down for storage so the gearcase and cooling passages drain by gravity. That single detail prevents the most common freeze damage on any trailerable boat, and it costs nothing.
Clean the Tubes Before They Sit
A season leaves a brown or gray band along the waterline of aluminum toons, from mineral deposits, algae film and oxidation. Leaving that on the metal for five or six months makes it considerably harder to remove in spring. Wash the tubes down and treat the waterline while the boat is still warm out of the water.
Aluminum wants a cleaner made for it. Many pontoon cleaners are acid-based and are effective precisely because of that, which also means they need care around trim, decals, carpet and skin, so follow the label on dwell time and rinsing. Our pontoon cleaning walkthrough covers the method and the products in detail.
Strip and Dry the Deck
Everything that can come off the deck should. Loose cushions, the table, cup holders, the cooler, life jackets and anything stored in the bow compartments all go home. Wet or damp items sealed under a cover for a winter are how a pontoon develops a smell it keeps for years.
Handling Fixed Furniture
Bases that are bolted down stay put, but the seat bases open. Lift the lids, empty the storage below, wipe the compartments dry, and prop the lids ajar so air can move through. Clean the vinyl with a marine vinyl cleaner before storage rather than after, since spring cleaning has to fight whatever grew over the winter as well as the original dirt.
Bimini, Canvas and Enclosures
Take the bimini down, let the canvas dry completely, and store it loosely rather than tightly folded. Canvas put away damp is a mildew problem waiting to happen, and hard creases from tight folding become permanent. Zippers and snaps benefit from a shot of dry lubricant before they sit through a cold season.
If the bimini stays on the boat under the cover, at least fold it flat and secure it so it cannot chafe against the cover from the inside. A bimini bow rubbing a cover through a windy winter will wear a hole in exactly the spot where water then gets in.
The Cover Is the Hard Part
A pontoon cover has to span a wide, flat deck with no natural peak, so pooling is the default outcome unless you build in support. A proper pontoon support system uses adjustable poles plus webbing straps to create ridges that force water to the sides. Taylor Made, for example, sells a pontoon cover support system with adjustable poles and polypropylene webbing.
Ventilation matters just as much. A completely sealed cover traps deck moisture against furniture for months. Use a cover with vents, or add vents, and add a moisture absorber under the cover for the interior air. Cover sizing for pontoons follows different logic than V-hull covers, which our pontoon cover fitment guide walks through.
Pontoon Winterization at a Glance
| Area | What to do | Skip it and | Timing |
|---|---|---|---|
| Outboard | Treat fuel, flush, fog, change oils | Fuel deposits and corrosion | First, engine warm |
| Tubes | Wash and treat the waterline band | Stain sets in over months | Right after haul out |
| Furniture | Clean vinyl, empty and prop bases | Mildew and lasting odor | Once the deck is dry |
| Bimini | Down, fully dry, loosely stored | Mildew and set-in creases | Before covering |
| Battery | Out, charged, on a maintainer | A frozen, ruined battery | Any time before storage |
| Cover | Support poles, straps, vents | Pooling water and torn fabric | Last step |
Mistakes Pontoon Owners Make
The biggest is covering a pontoon without any support underneath. On a flat deck the cover sags in the middle, collects rain, then holds ice, and the weight either tears the fabric or bends the frame it is strapped to. Support poles and webbing cost a fraction of a replacement cover.
The second is leaving furniture cushions flat on the deck under a sealed cover, where condensation settles and stays. The third is putting the tube cleaning off until spring, when the stain has had all winter to bond to the aluminum.
Frequently Asked Questions
Do pontoon tubes need anything special for winter? They need cleaning before storage rather than any special treatment. Aluminum handles cold fine, but a season’s waterline stain left on the metal for months becomes much harder to remove. Wash and treat the tubes right after the boat comes out.
Can I leave a pontoon in the water over winter? That depends entirely on whether your water freezes and what your marina allows. In a freezing climate, ice movement can damage tubes and dock hardware, which is why most owners in those regions haul out. Ask your marina, since local practice varies a lot.
Should I shrink wrap a pontoon or use a cover? Both work if they are done properly. Shrink wrap sheds water well but is a single-season expense, while a good cover on a real support system is reusable. Either way the deciding factor is whether water sheds and whether the enclosed air can ventilate.
Do I need to remove the pontoon furniture? Not the bolted bases, but loose cushions, tables and anything in the storage compartments should come off. What stays should be clean, dry and able to breathe under the cover.
Where does the battery go? Out of the boat and somewhere it will not freeze, ideally on a maintainer suited to its chemistry. A discharged battery freezes far more easily than a charged one, which is why the neglected one is usually the one that cracks.
Does a pontoon need antifreeze? Only for water systems it actually has. Many pontoons have no plumbing beyond a livewell or a sink, in which case draining is enough. Anything that holds water and will not drain gets non-toxic marine antifreeze instead.
The Bottom Line
Pontoon winterization is an outboard job plus a deck job. Do the engine exactly as you would on any trailer boat, then clean the tubes before the stain sets, strip and dry the furniture, store the bimini loose and dry, pull the battery, and cover the deck over a real support system with vents. The engine side is detailed in our winterization checklist, and the tube work is in our pontoon cleaning guide.