Father's Day timing. Father's Day lands on the third Sunday in June, so the otter dad gift t-shirt should be ordered by early June to leave room for standard delivery before the holiday morning.
Match to his closet style. Some otter dads wear loud graphic shirts on weekends; others stick to single-color t-shirts with a small chest print. The designs in this guide split between bold illustration and quieter typography, so the choice comes down to which side of the closet he leans toward.
Pun-tolerance. Otter humor leans heavily on water-puppy and significant-otter wordplay. A dad who repeats those puns out loud will wear the verbal designs proudly; a dad who rolls his eyes at puns will be happier in the retro illustration or anatomy-chart angle.
Wear beyond the occasion. A Father's Day t-shirt that lives in the rotation past June 30th holds value longer than a holiday-only graphic. Look at whether the design reads as a permanent otter dad piece or only as a June moment.
Print legibility at conversation distance. On the verbal designs, the text is the joke. If a coworker cannot read the punchline from across a room, the shirt does less work. Larger type and high contrast layouts hand the joke off faster than busy compositions.