Here is a list of the gyms in Brisbane who offer a free gym trial:
Anytime Fitness Australia: 7-day
Anytime Fitness offer a 7-day free trial gym pass.
Fernwood Fitness: 7-day
Fernwood Fitness has 69 premium women-only health clubs around Australia. You can receive your free 7-day pass on their website.
Goodlife Gym: 5-day
Goodlife Health Clubs provide 24/7 access and a 5-day free pass to try out one of their clubs.
Jetts Gym: 3-day
Jetts offer a free trial with a 3-day gym pass – just fill in the online form on the website.
Snap Fitness: 3-day
You can get started at Snap Fitness with a 3-day pass. Snap gyms are located in over 2,000 locations worldwide and offer 24/7 access.