How to throw an under-the-sea party for a 4 year old

By Little Ocean Explorers · Updated 18 October 2026

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Under the sea is one of the easiest party themes to pull off at home, and it looks amazing with very little effort. Here's the plan we'd follow for a room full of excited four year olds.

Invitations

Send them two to three weeks ahead. Our own editable sea-life invites can be personalised in Canva, then printed or sent by phone. They are instant digital downloads; nothing is posted.

Decorations

• Blue and green balloons with green streamers hanging down like seaweed.
• Paper fish on the walls, made by the birthday girl or boy the week before (a lovely pre-party craft).
• A blue tablecloth 'sea' with toy sea creatures swimming across it.

Food

• Goldfish crackers, 'seaweed' cucumber sticks and jelly 'rock pools' with gummy fish.
• A wave-iced cake topped with toy sea creatures that double as a present.

Games four year olds love

• Magnetic fishing game.
• 'Sharks and fish': musical statues, but the shark catches anyone still moving.
• A shell treasure hunt round the garden.

Party bags

A mini ocean sticker book, a small sea creature figure and a shell-shaped chocolate. Done. Baker Ross has a whole sealife section of stickers, figures and fillers that fit this theme perfectly.