Dogs and their owners can celebrate Halloween by the water at The Cleat in Bill Baggs Cape Florida State Park on Saturday, Oct. 31.

The second annual Howl-O-Ween opens at 2 p.m., with the dog costume contest beginning at 7 p.m., according to Lighthouse Restaurants’ current registration page. The venue is at 1200 Crandon Blvd., Key Biscayne.

Registration and park entry

Attendance is free for owners and dogs, but dogs entering the costume contest need a separate contest registration. Select the appropriate ticket option and check its current price when registering. Dogs may attend without competing.

The state park entrance fee is separate. The organizer lists $8 per vehicle carrying two to eight people, or $4 for a single-occupant vehicle or motorcycle.

Contest categories include Cutest Monster, Spookiest Duo for dog-and-owner costumes, and Best in Show. Food, drinks and dog-friendly treats will be sold.

Dogs must be well-behaved, attended and on a 6-foot leash. Bring waste bags. The outdoor event is weather-dependent; check the organizer’s updates before heading out.