Broome's crab racing season has been thrown into doubt by the apparent theft of the host's famous hat made out of one of the giant crustaceans.

Owen Pointer – known in the Kimberley as 'Rabbit' – has been donning the enormous hat for the past 21 years as host of the hermit crab event.

"The hat is basically a very large mud crab, almost a metre long if you include the legs and everything," Mr Pointer said.

"It's one you wouldn't be able to buy at the local shops, because I spent weeks making it."

Hermit crab racing is known for its slow pace and rowdy crowds.

In Broome, it has been embraced by both locals and tourists, who pack into a local pub on Sunday evenings to make a donation to charity and place a bet on one of the small, freshly collected crabs.

But this year's racing season, due to start at the Easter long weekend, may not go ahead because of the apparent theft.

Owen Pointer says hermit crab racing may be cancelled if he does not get his hat back. ( ABC News )

Last Thursday Mr Pointer went to the pub's storeroom to collect his unique headgear, but it had vanished.

"I went to grab the hat to do some TLC on it before we start the season, and lo and behold it wasn't there," he said.

"I'm hoping someone might have just taken it as a drunken lark, and if they have, they just need to return it, even if it's anonymously, through a third party.

"It's an integral part of the show, which helps raise a lot of funds for organisations and charities, and I'd hate to see it spoilt because of something like this."

Hotel staff are now trawling through two weeks' worth of CCTV footage to try to spot the thief.

Anyone who has seen a large, crab-themed hat is asked to call the Broome police station.