タトゥーがあるんだけど、ジム利用できるかな？ — I have a tattoo, can I use the gym? (Gym · Fitness, Casual — to friend, JLPT N4)

Gesture & etiquette

Smile warmly and give a friendly thumbs-up or a casual wave of the hand.

Some private gyms or traditional public facilities in Japan have strict no-tattoo policies, so always check the specific rules of the gym beforehand.