Don't bother seasoning a new cooler.

You don’t need to. The whole “seasoning” thing is a myth that refuses to die, mostly recycled from old metal coolers or overzealous forum posts.

Modern rotomolded coolers (Yeti, RTIC, etc.) are built to perform out of the box. The gasket will seal fine after a few uses. The insulation doesn’t need to “settle.” The only thing that actually helps is pre-chilling the cooler before loading it with cold stuff.

Do this: toss a bag of ice or a few frozen water bottles in the cooler an hour before you pack it. That way the interior is cold and won’t steal energy from your drinks. That’s it.

If you absolutely must “season” something, season your expectations. A cooler that’s already cold works better than one that isn’t.