すみません、わさび抜きで、まぐろをお願いできますか？ — Excuse me, could I get tuna without wasabi? (Sushi · Restaurant, Formal — to staff, JLPT N4)

Gesture & etiquette

Make eye contact with the sushi chef or server and raise a hand slightly to get attention.

At some conveyor belt sushi places, special orders might be limited or take longer. For severe allergies, consider showing an allergy card in Japanese.