World Museum, Liverpool
Five floors, free, and it covers three things small children reliably love: giant dinosaurs, an aquarium and a space gallery. The best wet-weather day within half an hour.
Calderstones Park
Liverpool, Merseyside
South Liverpool's favourite park: lake, playground, botanical corners and the Storybarn - The Reader's hands-on storytelling house in the old coach yard. The Calder Stones themselves are older than Stonehenge, a fact children deploy for weeks.
Storybarn sessions book out - reserve ahead. The park around it is free and generous; the Garden Party in mid-August is the free event of the south-Liverpool summer.
Looking for more parks & outdoors near Liverpool?
Also in Liverpool
Speke Hall
A Tudor hall with woodland walks, a maze and a natural play area in the grounds. Free if you have National Trust membership, and the indoor house is a good rain fallback.
Museum of Liverpool
The city's story with an overhead railway carriage to climb aboard and Little Liverpool, a dedicated hands-on gallery for under-6s. Free, on the waterfront, and the window views are half the fun.
Merseyside Maritime Museum
Titanic and Lusitania told in the city that crewed them, ship models, and the Seized! customs gallery in the basement where kids hunt smugglers. Free, and the Albert Dock outside is its own event.
Mersey Ferries River Explorer
The famous ferry across the Mersey run as a 50-minute sightseeing loop with commentary, and the honest truth is kids love the boat more than any museum. Hop off at Seacombe for Eureka! next door.
Croxteth Hall & Home Farm
A working Edwardian estate farm with rare breeds, a walled garden and 500 acres of free country park around it. The farm entry is cheap and the pigs are enormous.