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I was really getting into kayaking in the late ’90s after taking a continuing education class in kayaking at the University of Memphis.

Loved it!

They taught us how to use sit-in kayaks. There was no mention of sit-on-top kayaks so when I first saw a sit-on-top kayak at an outfitter, I was unsure of the boat, especially the holes in the bottom.

Maybe you’re the same as I was? Or maybe you’d like to learn more about how to use scupper plugs and their alternative, scupper valves?

Due to my naive preconception, I avoided sit-in-kayaks for years. I had thought they lacked in quality.

Don’t make my mistake.

Both sit-on-top kayaks and sit-in kayaks are amazing boats. Depending on your adventure one type may be better than the other. Sit-in kayaks are better for whitewater adventures where sit-on-top kayaks are the preferred fishing kayak.

Let’s go over scupper holes, scupper plugs, and scupper valves… what they are and how they’re used.

The Purpose of Scupper Holes in Sit-On-Top Kayaks

Scupper holes of a Wilderness Systems Tarpon 105 sit-on-top kayak.

Why does your kayak have holes in the bottom?

Well-spaced holes in the bottom of sit-on-top kayaks are self-bailing holes called scupper holes. Scupper holes in the kayak’s hull are designed to allow water that splashes inside or drips off the paddle to drain out instead of pooling in the floor of the kayak.

So if you’re wondering if your sit-on-top kayak should have open holes in the bottom, yes, scupper holes are a normal feature.

The self-bailing feature of scupper holes works to keep paddlers comfortable and safe by improving efficiency.

The additional weight of water in a kayak makes it heavier and more difficult to maneuver.

Without scupper holes in a sit-on-top kayak, a kayaker has to periodically empty water by flipping the kayak (often inconvenient) or by using your bilge pump and/or sponge, two kayak safety items that you should have.

Some kayakers intentionally plug their scupper holes. Scupper plugs aren’t used to keep your kayak from sinking. It will not sink if the holes are left open. Kayakers use scupper plugs to bypass the self-bailing feature.

Let’s take a look at how these plugs work and why you might consider using them too.

The Purpose of Scupper Plugs for Sit-On-Top Kayaks

Harmony scupper plugs installed in each of the front four scupper holes of a Wilderness System sit-on-top-kayak.

Scupper holes in sit-on-top kayaks are for self-bailing but the pressure of waves against the hull can force water back up through the holes. This can cause problems in colder weather when cold water can have a great effect on you physically.

Scupper plugs to the rescue!

They help keep your sit-on-top kayak drier as long as rainy weather isn’t an issue and water isn’t continually splashing onto your kayak.

How do you use scupper plugs? Just pop them in the holes to keep the cold water out. You might want to keep one or two scupper holes open to provide the perfect balance of drainage and a dry deck or you can remove one as needed, use a few scupper valves, use a bilge pump, or a sponge to get rid of excess water.

Excess water impairs kayak performance so don’t let water buildup on you.

Do You Have to Use Scupper Plugs on a Kayak?

Do you need scupper plugs in warmer weather? Not at all. Most of us like getting a little wet when kayaking. It’s sorta the nature of the sport and it keeps you much cooler on hot days.

Can you use a kayak without scupper plugs in colder weather? Yes, you can use your kayak without scupper plugs in colder weather but be sure to wear the right clothes like one of these drysuits over at Backcountry. You don’t want hypothermia.

How to Install Scupper Plugs

Harmony scupper plug installed in a Wilderness System sit-on-top-kayak.
A scupper plug for a sit-on-top kayak that prevents water for splashing up through a scupper hole and also blocks water from draining out the hole as well.

How do you install scupper plugs? All you have to do is push these pliable rubber plugs in the scupper holes. Make sure you have the right size though.

Are scupper plugs universal? Yes and No. Scupper holes come in different sizes and shapes. The holes in some kayaks are all the same size and other kayaks have scupper holes that vary in size and shape.

When buying a universal plug, look for a plug with the proper fit for your scupper holes. For instance, these universal scupper plugs are a great product that fits any kayak scupper hole up to 1.25 inches.

Scupper Valves

A scupper valve for a sit-on-top kayak. Scupper valves allow water to drain out the scupper hole but not come back up.

How does a scupper valve work? Scupper valves are one-way plugs. They allow water that enters a sit-on-top kayak to drain out the scupper holes while also blocking water from splashing up through the holes.

So why on earth wouldn’t everyone use scupper valves?

  • Availability: Scupper valves are not available for all sit-on-top kayaks. Ocean Kayak Scupper Valves are the best I’ve found. They are medium-sized scupper valves for round-shaped holes.
  • Maintenance: You have to keep debris from building up around the valve. If the valve is blocked, it won’t work properly.
  • Expense: Scupper valves are slightly more expensive than scupper plugs.
  • Inconvenience: Many scupper valves will stick up above the deck where plugs have a more flush fit. Because they stick up they are easier to damage or dislodge.
Ocean Kayak Scupper Valve for a sit-on-top kayak.

Note: I tried installing this scupper valve on this Wilderness Systems Tarpon 105. It was close but did not fit. It’s hard to tell from the angle of the photo but the plastic base of the scupper valve was the same size as the scupper hole. I did research this before buying. Many sites selling this plug say it fits the Wilderness Systems Tarpon. No such luck for me.

Using Scupper Plugs and Scupper Valves Together

Closing the scupper holes around your feet and legs with scupper plugs and using scupper valves near the kayak seat is an efficient use of resources. It also reduces your chances of damaging or dislodging a valve. You’re less likely to knock into a scupper valve close to or under your seat.

By strategically using scupper valves and plugs, you can save a few dollars and won’t have to worry as much about periodically draining water from the deck.


Should you plug scupper holes?

It’s a matter of personal choice but I’m for using them to stay dryer in colder weather.

The major downside to using scupper plugs is losing the self-draining benefit of sit-on-top kayaks. When water builds up in the floor of the kayak, there is a loss in buoyancy and maneuverability which is a matter of safety.

If you use scupper plugs, be sure to carry a sponge and or bilge pump for draining the water from your kayak. These items should be part of your kayak safety kit.

Don’t have a kayak safety kit? NRS has a kayak safety kit that will get you started. But be sure to check out our post “Canoe & Kayak Safety Equipment Checklist” for a complete list of safety equipment for your kayak.

I wanted to mention one additional thing that I touched on in the introduction. Classes.

Kayak classes are great for learning safety techniques. They’re also great for meeting new friends. I made wonderful lifelong friends through that class I look.

Stay safe and have fun out there!

A pack of four kayak scupper plugs and a pack of two scupper valves for use in a sit-on-top-kayak.
Steve Hood

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  1. Avatar for Charles Cooper Charles Cooper says:

    Hi Steve
    I have been canoe and kayak (fly) fishing for 70 of my 82 years and was kayak fishing way before it became popular. I presently have 5 hardshell and 3 inflatable kayaks (too many)
    although I have 2 favorites, I lend the rest out to friends.
    I owned 1 SOT and will never get another one, I had scupper leakage from the start and nothing I did solved it, I eventually junked the boat. Scupper walls are naturally thin as they are stretched during manufacture, much more open to cracks and failure, I will never buy a 2 piece boat, a friend of mine actually had his boat separate at the seams when used in salt water.
    Just my experience and opinion.

    1. Hello Charles! Thank you for sharing your valuable insights. Yes, scupper holes are notorious for cracking and leaking.

  2. Avatar for Kevin Jones Kevin Jones says:

    Scupper holes leaking.
    New sot kayaks are much better.
    Only way they will leak is if they’re mistreated by putting transportation wheels through the scupper holes like I did on my first wilderness tarpon 100 eventually wore the plastic thin and water got in where it shouldn’t. I sealed the scupper holes completely and use that kayak on the canals only still good for estuary no leaks.
    Purchased 2 more wilderness kayaks a tarpon 140 with rudder and a tarpon tandem 135T both amazing on the water the 140 is fabulous with the added rudder big big difference. Always used plugs but now looking at the G2 but see you had issues with sizing pity as now puts me off going down that route. Anyway, for me scuppers are great in a sit on top kayak.
    Used to have a Canadian pelican huge boat for all the family lovely to paddle and carry picnic etc. Sold due to child growing up. Thanks for reading.