Get a cooler with at least two inches of insulation.

Yes, for 8+ hours on a hot beach, you need a cooler built for it. The cheap foam or thin-walled models will leave you with a lukewarm puddle by lunch.

The key is insulation thickness. Rotomolded coolers (like Yeti, RTIC, or Pelican) have 2-3 inches of foam and are basically ice chests. They keep ice for 24+ hours. But you don’t need to spend $300. A good-quality mid-range cooler (like a Coleman Xtreme with 2-inch walls) will get you 10-12 hours if you do your part.

Your part: pre-chill the cooler with ice packs the night before, use a high ice-to-contents ratio (2:1 or more), and keep it out of direct sun. Also, drain melted water only when necessary — cold water helps insulate. Drain it all and the ice melts faster.

A rotomolded is overkill for a single beach day, but a basic Coleman with thin walls is a gamble. The sweet spot is a cooler with at least 1.5 to 2 inches of insulation and a tight-sealing gasket. And throw a towel over it. That alone adds an hour or two.

Don’t overthink it: buy a cooler designed to hold ice, then help it do its job.