How Long Can Red Eared Sliders Be Underwater?

You’re watching your red-eared slider chill at the bottom of the tank, and a thought hits you: when was the last time this little guy came up for air?

Red-eared sliders typically stay underwater for 5-7 minutes during normal activity, but they can hold their breath for up to 30-45 minutes if needed. When sleeping, they can stay submerged for several hours. During winter brumation, they can survive underwater for 2-5 months straight.

Yeah, you read that right. Months.

But here’s the thing: there’s a huge difference between casually holding their breath and going full survival mode. Let’s break down what’s really going on when your turtle plays submarine.

Understanding how long red eared sliders can hold their breath helps explain why they spend so much time comfortably submerged.

How Red-Eared Sliders Actually Breathe

First things first: red-eared sliders have lungs, not gills.

They’re not fish. They’re reptiles who happen to love water, which means they absolutely need to surface for air eventually.

When they’re just hanging out underwater, they’re literally holding their breath like you would in a swimming pool. Their lungs work exactly like ours do—breathe in air, extract oxygen, breathe it out.

The difference? They’re way better at it than we are.

The Butt-Breathing Myth (Sort Of)

You’ve probably heard that turtles can “breathe through their butts.” It sounds like internet nonsense, but there’s actually some truth to it.

Red-eared sliders have specialized blood vessels in their cloaca (the opening under their tail) that can absorb small amounts of oxygen from water. Scientists call this “cloacal respiration,” and turtle fans call it butt-breathing.

Here’s the catch: this only provides about 10% of the oxygen a fish’s gills would extract. It’s a backup system, not their primary breathing method.

Think of it like sipping water through a coffee stirrer when you’re dying of thirst. Sure, technically you’re drinking water, but you’re not exactly hydrated.

This cloacal oxygen absorption is most useful during brumation when their metabolism drops to almost nothing. For everyday life? Your turtle still needs those lungs.

While red eared sliders can extract oxygen through their cloaca, they’re not the champions of this adaptation—learn about which turtle species are true butt-breathing experts and how this ability evolved.

The Normal Underwater Timeline

Here’s what scientists and turtle owners have observed:

• Active turtles: 5-7 minutes between breaths
• Resting turtles: 30-45 minutes
• Sleeping turtles: 3-9 hours
• Brumating turtles: 2-5 months

One turtle owner timed their sliders for weeks and found their 4-year-old stayed down for 11 minutes on average, while their 6-year-old managed 15 minutes. Both came up way before they actually needed to.

That’s normal turtle behavior. They don’t push it to the limit unless something’s forcing them to hide.

For comprehensive information about out-of-water survival across all turtle species and the factors that affect it, see our full guide on how long turtles can stay out of water.

Tank Size Matters More Than You Think

Here’s something that surprised me when I first learned it: the size of your tank directly affects how long your turtle can stay underwater.

Small tank = less water = less dissolved oxygen = turtle needs to surface more often.

It’s not just about giving them swimming space (though that matters too). The water chemistry itself changes in smaller volumes.

A 10-gallon tank with one turtle will have way less available oxygen than a 75-gallon setup. Your turtle might need to surface every 15-20 minutes in a small tank, while the same turtle in a bigger tank could comfortably stay down for 30-40 minutes.

This is why proper filtration and tank size aren’t just recommendations—they’re life support.

What Affects Underwater Time?

Activity Level

A turtle hunting food or freaking out about something can only stay down for 7-10 minutes max.

Swimming burns oxygen fast. The more they move, the more they breathe.

Water Temperature

Cold water = longer dive times.

When water temperature drops, their metabolism slows down, they need less oxygen, and they can hold their breath longer.

This is why the whole “months underwater” thing only happens in winter.

Age and Size

Adult turtles outlast babies by a significant margin.

Hatchlings have tiny lungs and need to surface more frequently. Adults have bigger oxygen reserves and better breath control.

Health Status

A sick or stressed turtle might surface constantly, even if the water conditions are fine.

If your normally chill turtle suddenly becomes a compulsive surface-breather, something’s wrong.

The Brumation Superpower

This is where things get absolutely wild.

During brumation (the reptile version of hibernation), red-eared sliders can stay underwater for 2-5 months without coming up for air once.

Not a single breath.

How Is This Even Possible?

When temperatures drop below 50°F, their entire body goes into power-saving mode:

• Heart rate drops from 40 beats per minute to about 10
• Metabolism crashes to almost zero
• Oxygen needs become minimal
• They switch to anaerobic respiration (producing energy without oxygen)

At 3°C (about 37°F), research shows red-eared sliders can survive 4-5 months with zero oxygen. They basically shut down to the absolute bare minimum needed to stay alive.

Even crazier? They use calcium from their shells to buffer the acidic toxins that build up when they’re not breathing oxygen. Their shells literally act like antacids.

Nature is ridiculous sometimes.

Where Do They Brumate?

Wild red-eared sliders bury themselves in the mud at the bottom of ponds and lakes. They’ll occasionally come up during warm spells to bask, then dive back down when it gets cold again.

In captivity, most pet turtles don’t brumate because indoor temperatures stay too warm. That’s actually fine—they don’t need to brumate to be healthy (though it can help with breeding if you’re into that).

If your indoor turtle seems lethargic in winter, that’s probably because your room got a bit too cold. Temperatures between 40-70°F create a “death zone” where they’re too cold to function properly but not cold enough to fully brumate.

Keep their water at 75-84°F and they’ll stay active year-round.

Can Red-Eared Sliders Drown?

Yes. Absolutely yes.

People assume aquatic turtles can’t drown, but they have lungs, not gills. If they can’t reach the surface, they will run out of oxygen and drown.

Common Drowning Risks

• Getting trapped under decorations – That cute castle cave might be a death trap for a baby turtle
• Tank items falling – Rocks, driftwood, or basking platforms (my pick: floating basking platform) can pin a turtle underwater
• Exhaustion – Sick or injured turtles might not have the energy to swim up
• Deep water without resting spots – Especially dangerous for hatchlings

This is why your tank setup matters. Always provide:

• Easy access to the surface
• A basking platform they can climb out on
• No tight spaces they could get wedged into
• Appropriate water depth for their size

Baby turtles need shallower water than adults. If your hatchling’s tank is a foot deep, they’re working way too hard just to breathe.

Why Your Turtle Won’t Leave the Water

If your red-eared slider is refusing to come up, something’s wrong.

Common causes:

• The water’s too cold – They don’t want to leave because they’re trying to conserve energy
• The basking spot sucks – Maybe it’s too hot, too cold, too slippery, or too dirty
• They’re scared – Is there a cat staring at them? Loud noises nearby?
• They’re sick – Illness can make it hard to move or leave the water
• They’re brumating – If it’s winter and your room got cold, they might be semi-brumating

Check your temperatures first. Water should be 75-84°F, basking area should be 85-90°F.

If temperatures are good but behavior is off, vet time.

Why Your Turtle Won’t Go IN the Water

On the flip side, sometimes they avoid the water entirely.

• Dirty water – Would you want to swim in your own toilet?
• Wrong temperature – Too hot or too cold, they’re not going in
• pH problems – Wrong water chemistry can irritate their skin
• They’re pregnant – Female turtles come out to lay eggs
• They’re being bullied – If you have multiple turtles, someone might be getting picked on
• They’re sick – Respiratory infections make swimming harder

The fix usually involves better tank maintenance. Change 25-50% of the water every 2 weeks, clean the whole tank monthly, and keep the temperature stable.

If you’re doing all that and they still won’t swim, something’s medically wrong.

How Long Can They Go WITHOUT Water?

Different question, equally important.

Red-eared sliders can survive 3-5 days without water, depending on their age and health.

They technically can last longer—their breathing system works fine on land—but they need water to swallow food. Red-eared sliders can’t eat unless they’re in water.

Since they typically eat every 2-4 days, going without water for a few days won’t kill them. But it’s definitely not ideal.

Never intentionally leave your turtle without water access. Even if they’re basking for hours, they should always be able to get back to water when they want.

The Bottom Line

Your red-eared slider is an underwater ninja with some seriously impressive breath-holding skills.

• For normal daily life: They’ll come up every 5-30 minutes
• When sleeping: A few hours is totally normal
• During brumation: They can literally survive months without air

The real trick isn’t just about how long they can stay underwater—it’s about giving them an environment where they don’t have to push those limits.

Clean water, proper temperature, good tank size, and easy access to the surface. That’s what makes the difference between a stressed turtle constantly gasping for air and a happy turtle who cruises up whenever they feel like it.

Your turtle isn’t trying to set any records. They’re just trying to vibe in peace.

Let them do that, and they’ll be perfectly fine underwater—coming up on their own schedule, thank you very much.