The Ahi tuna may cook more slowly or quickly on the grill, depending
on how thick it is. If it's a little on the thick side, it may take a
few minutes longer than what the recipe calls for. Cooking ahi tuna
until an instant-read thermometer
reaches 140 F to 145 F is USDA recommended, but tuna and swordfish
steaks are often cooked to medium-rare, which is an internal temperature
of around 125 F.
Recipe courtesy of The Spruce Eats