Under the Sea Children’s Books to Explore

If your little one is wild about whales, mesmerised by mermaids or constantly asking questions like “how deep is the ocean?” — you’re not alone. Children are naturally drawn to the sea. It’s vast, mysterious, and filled with fascinating creatures. Whether it’s the sway of seaweed or the sparkle of a seahorse, ocean life seems to unlock something magical in young imaginations.

That’s why under the sea children’s books are such a brilliant way to nurture their natural curiosity. They’re not just lovely to look at — the best ones are full of opportunities for early learning, emotional development, and storytelling too. From colourful picture books about the ocean for children to fascinating non-fiction ocean books for children, the right story can spark a lifelong interest in marine life, conservation, or simply the joy of reading.

“I just want something they’ll love and learn from…”

I’m Catriona — I’m an early childhood educator, and I work closely with the team at BeoVERDE to select books that genuinely support children’s learning and emotional growth. Whether I’m talking to a busy parent or helping a teacher find books for a seaside-themed classroom corner, I hear this kind of thing all the time:

“They love the ocean, but I don’t know what book is right for their age.”
“I want something they’ll actually engage with.”
“We’re trying to move away from plastic toys — are there books that can do the job of teaching and entertaining?”

The answer is yes — absolutely — but I’ll be honest, the search can feel a little overwhelming at first.

Why it’s tricky to find the right sea-themed book

There’s no shortage of ocean-themed storybooks for kids on the market. But not all are created equal. Some books have dazzling covers but paper-thin stories. Others are too complex for younger readers, filled with dense facts or overwhelming illustrations that don’t hold a child’s attention.

You might find yourself scrolling online or standing in front of a bookshelf wondering:
🌀 Will they grow into this?
🐠 Is this too babyish?
🐙 Will this help them learn — or just look pretty on a shelf?

When you’re already juggling a million decisions as a parent or educator, this shouldn’t be one more stress point.

So here’s what I’ve done for you

I’ve put together a carefully curated list of the best under the sea books for toddlers, preschoolers and early primary-aged children. These aren’t just the usual suspects — they’re books I’ve used in classrooms, gifted to friends, and seen children return to again and again.

Every book on this list is:

📚 Matched to the right age range — so you know it’s suitable developmentally

📖 Beautifully illustrated and designed to hold attention through repeated reading

🐬 Rich in both storytelling and educational value — whether that’s building emotional vocabulary, exploring habitats, or sparking big blue questions

There’s a bit of everything here — mermaid books for young readers, educational sea books for primary school, even sea-themed board books for babies and toddlers — all handpicked to bring joy and insight into your little one’s world.

And throughout, you’ll find practical tips and ideas to extend the learning: from setting up a sea-life reading corner, to making sensory trays inspired by jellyfish and waves, or simply using storytime to talk about how we can care for our oceans.

If you’ve ever wondered what makes a book truly engaging — this is where I’d start. These titles go beyond the page. They invite questions, build confidence, and help children make sense of the world in all its wonder.

Ready to explore? Let’s dive in.

Ages 3–5 | Gentle Wonder & Mermaid Magic

Mermaid Lullaby

Recommended age: 3–7 years
A soft and soothing bedtime story featuring gentle rhymes and glowing artwork. Ideal for calming down at the end of the day or for children who love gentle mermaid magic.

In the Land of Mermaids

Recommended age: 3–6 years
With dreamy watercolour illustrations and a warm message of friendship, this book invites little readers to imagine life beneath the waves.

🎓 Educator insight: These books are perfect for encouraging imaginative storytelling and role play. Try asking your child to invent their own mermaid character after reading.

Ages 4–8 | Curious Explorers & Big Questions

My First Book of Sea Creatures

Recommended age: 4–8 years
A colourful and accessible introduction to marine life, this non-fiction book is ideal for early learners who love spotting, naming and remembering real sea creatures.

Explore the Ocean: Adventures under the Sea with Emma and Louis

Recommended age: 7–10 years
Follow two adventurous kids through coral reefs, sunken ships and deep-sea mysteries. A brilliant mix of storytelling and marine biology.

Deep in the Ocean

Recommended age: 3–5 years
Richly illustrated and packed with discovery, this book is a treasure trove of facts and visual storytelling. Perfect for shared reading and repeat exploration.

🎓 Bookseller tip: These are great choices for building early non-fiction literacy. Children love linking real-world facts with what they’ve seen in aquariums, nature shows or seaside trips.

Ages 5–7+ | Big Blue Thinking & Laughs Along the Way

5 Minute Ocean Stories: True Tales from the Sea

Recommended age: 5+ years
From coral reefs to underwater volcanoes, these short true stories are perfect for bedtime or the classroom. Each tale teaches something new and exciting about the ocean.

Into the Deep Sea: An Exploration of Our Oceans

Recommended age: 7–10 years
Dive layer by layer into the ocean’s depths. This beautifully illustrated non-fiction book explains how the ocean works — from currents to creatures — with clarity and visual style.

Sharks: A Mighty Bite-y History

Recommended age: 8+ years
Full of bite-sized shark facts, this book is a firm favourite among kids who love sharks and their prehistoric predecessors.

🎓 Teacher insight: This age group thrives on combining facts with narrative. Books like these are ideal for topic-based projects and independent curiosity.

💡 Tips for Making the Most of Sea-Themed Stories

🐠 Set up a sea story station: Use blue fabric, soft sea toys, and shells to create an immersive reading corner.

🔍 Follow your child’s interests: If they love jellyfish or sharks, focus on those books first.

🐚 Add a sensory twist: Build an ocean sensory tray with water, stones, toy fish and plastic tubs for pouring.

🎨 Get creative: Encourage drawing sea creatures or creating underwater collages after reading.