Dehydrator is best for tuna jerky.

Use a dehydrator if you have one. It gives you more control and less risk of cooking the fish instead of drying it.

Ovens work, but they’re tricky. Tuna is lean and dries fast, and most ovens don’t go low enough to avoid cooking it. You want 145-155°F for jerky. If your oven can’t hold that range (many only go down to 170°F), you’ll end up with baked fish flakes instead of chewy jerky.

If you do use the oven: prop the door open a crack, use the convection setting if available, and check it like a hawk. Thin strips, maybe 1/4 inch, marinated or salted, and dry until it bends but doesn’t snap. Usually 2-4 hours.

Dehydrator is just set-and-forget at 145°F. Easier, more consistent, less risk of ruining expensive tuna.

Either way, start with sashimi-grade tuna. Canned tuna won’t work—too wet and fatty.