---
title: "Best Kids Water Bottle for School: Which One to Buy"
description: "The best kids water bottles for school: Thermos Funtainer, CamelBak Eddy+ Kids and Ion8, with the right size and lid for every age."
url: https://picksdesk.com/en/kids-family/best-kids-water-bottle-for-school
language: en
category: "Kids & Family"
kind: guide
byline: "Emily Carter"
editor: "Andrea Bertolotti"
publisher: "PicksDesk"
published: 2026-10-12
updated: 2026-10-12
tags: ["kids water bottle", "insulated kids water bottle", "water bottle for school", "straw water bottle", "thermos funtainer", "camelbak eddy", "back to school"]
products: ["Thermos Funtainer borraccia con cannuccia 355 ml (Thermos)", "CamelBak Eddy+ Kids 400 ml con valvola a morso (CamelBak)", "Ion8 borraccia per bambini 350 ml a prova di perdite (Ion8)", "Thermos Funtainer borraccia con beccuccio 470 ml (Thermos)"]
---

# Best Kids Water Bottle for School: Which One to Buy

> Insulated steel or lightweight plastic, straw, bite valve or spout: the four kids water bottles we recommend, from preschool to middle school.

Category: Kids & Family · Byline: [Emily Carter](https://picksdesk.com/en/team/emily-carter) · Published: 2026-10-12 · Updated: 2026-10-12 · Web version: https://picksdesk.com/en/kids-family/best-kids-water-bottle-for-school

For most elementary schoolers, the kids water bottle to buy is the 12 oz Thermos Funtainer with a straw: double-wall stainless steel that Thermos rates to keep water cold for up to 12 hours, and a push-button lid that stays leak-proof in a backpack when it's closed. Preschoolers do better with the lighter CamelBak Eddy+ Kids, and middle schoolers or kids in sports should step up to the 16 oz Funtainer with a spout.

### At a glance
- **Thermos Funtainer borraccia con cannuccia 355 ml** · For elementary school · $17–25
- **CamelBak Eddy+ Kids 400 ml con valvola a morso** · For preschoolers · $13–18
- **Ion8 borraccia per bambini 350 ml a prova di perdite** · On a budget · $10–15
- **Thermos Funtainer borraccia con beccuccio 470 ml** · For middle school and sports · $20–28

## How we picked

We don't physically test the products we cover. For this guide we cross-checked manufacturer specs from Thermos, CamelBak and Ion8, verified buyer reviews written months after purchase (that's when the real problems show up), and parenting coverage from US and European outlets. We dropped bottles with no replacement parts sold separately, and bottles that only change the cartoon character on the outside from one season to the next.

Our criteria, in order of weight:

- **Leak-proof when closed**, because the real test is a backpack dropped on the classroom floor.
- **One-handed opening** by the child, without asking the teacher for help.
- **Cleaning**: how many parts come apart, whether the straw pulls out, and whether replacement straws and valves are easy to find.
- **Size that fits the age** and the side pocket of the backpack.
- **Material**: insulated stainless steel or BPA-free plastic, each with its own trade-offs.

If you're shopping for the rest of the school gear too, our guide to choosing a [school bag](https://picksdesk.com/en/kids-family/school-backpack-how-to-choose) covers side pockets and back panels. The bottle should ride upright in a side pocket, not loose on top of the books.

## Best for elementary school: Thermos Funtainer 12 oz

The Funtainer straw bottle shows up in parenting guides on both sides of the Atlantic for a simple reason: it gets the two things that matter at school right. Your kid presses the button, the silicone straw pops up, and they drink without tipping the bottle. Closing the lid covers the straw again. The 18/8 stainless steel walls are vacuum insulated, and Thermos says drinks stay cold for up to 12 hours, which covers a full school day plus the bus ride home.

**Product: Thermos Funtainer borraccia con cannuccia 355 ml** (Thermos) · Best for: For elementary school
- Price band: Premium
- Specs: Capacity 12 oz (355 ml); Material 18/8 stainless steel; Technology Vacuum insulated, cold only; Type Pop-up straw; Dishwasher safe Yes (hand wash advised); Functions Handle, push button
- Key points: 18/8 stainless steel, double-wall vacuum insulation; Keeps drinks cold up to 12 hours (Thermos spec); Push-button pop-up straw with hygienic cover; Built-in carry handle; not for hot liquids

**Pro**

- Water is still cold at pickup, even in an overheated classroom.
- The straw is covered when closed, so it never touches the bottom of the backpack.
- Replacement straws are cheap and easy to find.

**Da sapere / Caveats**

- Cold drinks only: Thermos says it's not for hot liquids.
- A straw that gets chewed every day wears out and has to be replaced.
- Long-term reviews mention dents and chipped paint after a few drops.

**Who it's for:** kids ages 6 to 10 who are at school all day and drink when they're thirsty, not when someone reminds them.

## Best for preschoolers: CamelBak Eddy+ Kids 14 oz

At preschool, weight matters more than insulation. The Eddy+ Kids is made of Tritan Renew, a rigid plastic CamelBak says is free of BPA, BPS and BPF, and it weighs next to nothing when empty. It uses a bite valve: flip up the spout, bite down gently, and water flows without tipping anything. CamelBak calls it spill-resistant even when open, which is a practical detail with a four-year-old at the lunch table.

**Product: CamelBak Eddy+ Kids 400 ml con valvola a morso** (CamelBak) · Best for: For preschoolers
- Price band: Budget pick
- Specs: Capacity 14 oz (400 ml); Material Tritan Renew (plastic); Technology Not insulated; Type Bite valve straw; Dishwasher safe Yes; Functions Handle, flip-up spout
- Key points: Tritan Renew, free of BPA, BPS and BPF; Bite valve: no tipping needed to drink; Spill-resistant even when open (CamelBak spec); Lightweight, with built-in handle

**Pro**

- Light, with a handle small hands can actually grip.
- Valve and straw pull out and go in the dishwasher.
- The clear body shows how much water is left.

**Da sapere / Caveats**

- No insulation, so water warms up quickly in a hot room.
- Chewed valves wear out; replacements are sold separately.
- Some parents report drips when it rides on its side in a backpack, so keep it upright.

**Who it's for:** preschool through first or second grade, when the bottle has to be light and your kid is still learning not to knock it over.

## Best budget pick: Ion8 12 oz

The Ion8 is the bottle to buy when you already know it'll get left at the gym. It's BPA-free Recyclon plastic with a spout under a flip cover that swings back 240 degrees, out of your kid's face, plus a safety lock that keeps the cover shut in the backpack. There are no straws or valves, so it goes straight into the dishwasher and there are no tiny parts to lose.

**Product: Ion8 borraccia per bambini 350 ml a prova di perdite** (Ion8) · Best for: On a budget
- Price band: Budget pick
- Specs: Capacity 12 oz (350 ml); Material Recyclon plastic; Technology Not insulated; Type Spout with flip cover; Dishwasher safe Yes; Functions Handle, safety lock
- Key points: BPA-free Recyclon plastic; Flip cover opens 240° and locks; No small parts to take apart; Dishwasher-safe

**Pro**

- The easiest bottle in this group to clean.
- A lock you can see and hear click into place.
- Budget price range, so losing it isn't a big deal.

**Da sapere / Caveats**

- Kids have to tip it to drink, and little ones sometimes end up with a wet shirt.
- No insulation: by lunch, the water is room temperature.
- The seal depends on the lock; if your kid forgets it, the cover is just resting there.

**Best for:** a backup bottle that lives at school or in the car, or a kid who already drinks comfortably from a spout.

## Best for middle school and sports: Thermos Funtainer 16 oz

Around age 11, a straw starts to feel babyish, and 12 oz won't last through a morning with PE. The 16 oz Funtainer has the same vacuum-insulated steel as its smaller sibling, but with a wide spout under a push-button lid that locks. It drinks faster, refills easily at a gym fountain, and the gaskets come out for cleaning.

**Product: Thermos Funtainer borraccia con beccuccio 470 ml** (Thermos) · Best for: For middle school and sports
- Price band: Premium
- Specs: Capacity 16 oz (470 ml); Material 18/8 stainless steel; Technology Vacuum insulated, cold only; Type Wide spout; Dishwasher safe Yes (hand wash advised); Functions Handle, lid lock
- Key points: 18/8 stainless steel, double-wall vacuum insulation; Keeps drinks cold up to 12 hours (Thermos spec); Covered wide spout with locking lid; Removable gaskets for cleaning

**Pro**

- More capacity, with the same insulation as the straw version.
- Locking lid that won't pop open in a sports bag.
- Understated colors a sixth grader will carry without complaint.

**Da sapere / Caveats**

- Heavy when full; too much for a five-year-old.
- The wider body won't fit every narrow side pocket.
- Also cold drinks only, per Thermos.

**Makes sense for:** middle schoolers, after-school practice and day trips.

### Comparison
| | Thermos Funtainer borraccia con cannuccia 355 ml | CamelBak Eddy+ Kids 400 ml con valvola a morso | Ion8 borraccia per bambini 350 ml a prova di perdite | Thermos Funtainer borraccia con beccuccio 470 ml |
| --- | --- | --- | --- | --- |
| Best for | For elementary school | For preschoolers | On a budget | For middle school and sports |
| Capacity | 12 oz (355 ml) | 14 oz (400 ml) | 12 oz (350 ml) | 16 oz (470 ml) |
| Material | 18/8 stainless steel | Tritan Renew (plastic) | Recyclon plastic | 18/8 stainless steel |
| Technology | Vacuum insulated, cold only | Not insulated | Not insulated | Vacuum insulated, cold only |
| Type | Pop-up straw | Bite valve straw | Spout with flip cover | Wide spout |
| Dishwasher safe | Yes (hand wash advised) | Yes | Yes | Yes (hand wash advised) |
| Functions | Handle, push button | Handle, flip-up spout | Handle, safety lock | Handle, lid lock |
| Price band | Premium | Budget pick | Budget pick | Premium |

## Stainless steel vs. plastic: what changes in the backpack

Choosing between insulated steel and plastic is almost always a choice between temperature and weight. Vacuum-insulated steel keeps water cold for hours and doesn't hold on to smells, but it's heavier and it dents. A hard knock on the bottom can damage the vacuum between the walls, and from then on the bottle insulates less. Rigid BPA-free plastic, like CamelBak's Tritan or Ion8's Recyclon, is light and see-through, but the water ends up at classroom temperature.

Our rule of thumb: if your kid eats lunch at school and drinks mostly in the morning, steel is worth the extra weight. If they're in preschool and the bottle spends more time on a table than in a backpack, plastic makes more sense. We apply the same logic to everything else that goes to school. As with [kids headphones](https://picksdesk.com/en/tech/best-kids-headphones-for-school), what matters first is that your child can use it without help.

## Straw, bite valve or spout: it depends on age

A bite valve is the most forgiving: no tipping, and if the bottle falls over open, very little comes out. It's the right system for ages 3 to 6. The pop-up straw on the Funtainer works from about age 5 or 6, once kids can press the button and close the lid by themselves. A spout, locking or not, is for kids who already drink from a cup without spilling. From about third grade on, it's the fastest format and the easiest to wash.

One tip that applies to all of them: have your kid open and close the bottle as soon as it arrives, before the first day of school. A lid they can't work is a lid that stays shut.

*Photo: With a straw or bite valve, kids can drink without tipping the bottle.*

## What size to get

For preschool and the early elementary grades, 12 to 14 oz is plenty. Most schools have a water fountain or bottle filler, and a smaller bottle fits the side pocket and weighs less. From third or fourth grade, or for kids with afternoon activities, moving up to around 16 oz makes sense, especially on PE days. Past roughly 18 oz, a bottle gets bulky for a child and hard to keep upright in a backpack.

How much water your child needs isn't something a bottle decides; if you have questions, ask your pediatrician. The bottle's only job is to make drinking easy when they're thirsty.

## Cleaning and spare parts: the mistake that shortens a bottle's life

Almost every negative long-term review says the same thing: a smell, or dark specks in the straw or valve. It happens when the bottle sits closed with a little water in it from Friday to Monday. The fix is simple and works for every model here: empty it every evening, take out the straw and valve, run a thin brush through them, and let the parts dry separately with the lid open.

Thermos lists the Funtainer as dishwasher-safe but recommends hand washing so it lasts longer; CamelBak and Ion8 make no such distinction. Straws and valves are consumables, so keep a spare in a kitchen drawer and swap it out as soon as the silicone warps or tears.

> Put your kid's name on the bottom with a dishwasher-safe label, not on the lid. Lids are the part that gets swapped between classmates.

## Skip these if…

If you want a bottle for hot cocoa or warm milk, none of these will do: the Funtainers are designed for cold drinks only, and the two plastic bottles aren't insulated. You need a food jar or a thermos with a cup lid. Don't get the 16 oz Funtainer for a preschooler, since it's too heavy when full, and skip the Eddy+ if your kid chews everything, because the valve won't last.

## Our verdict

**Elementary school, full day:** the Thermos Funtainer 12 oz with a straw, because it keeps water cold and doesn't leak when it's closed.

**Preschool:** the CamelBak Eddy+ Kids, light with a bite valve; the Ion8 if you want to spend as little as possible or need a backup bottle.

**Middle school and sports:** the Thermos Funtainer 16 oz, with more capacity, a fast spout and a locking lid.

## FAQ

**Can you put hot drinks in an insulated kids water bottle?**

Not in the bottles in this guide. Thermos rates the Funtainer straw and spout bottles for cold drinks only, and the CamelBak and Ion8 bottles aren't insulated. For hot cocoa or soup, use a food jar or a thermos with a cup lid.

**What size water bottle is best for a preschooler?**

Around 12 to 14 oz. Anything bigger is heavy when full for a three- or four-year-old and often won't fit in a backpack side pocket.

**How often should you replace the straw or bite valve?**

When the silicone warps, tears or stays stained after washing. If your kid chews it, that can happen within a few months, so it's worth keeping a spare.

**Is stainless steel or Tritan better for a kids water bottle?**

Vacuum-insulated steel keeps water cold but is heavier and can dent; Tritan is light but doesn't insulate. We prefer steel for full school days and plastic for preschool.

**Are kids water bottles dishwasher-safe?**

All four bottles here are listed as dishwasher-safe. For the Funtainer, Thermos still recommends hand washing to make it last longer.

*Note: PicksDesk takes part in the Amazon Associates programme; prices are indicative market ranges to be checked on Amazon. The editorial team does not physically test products: assessments rely on official specs, verified reviews and specialist press.*