To get the absolute best protection at the beach, you should look for an SPF 50 broad-spectrum, mineral-based sunscreen with 80 minutes of water resistance.
While health organizations state that SPF 30 is the minimum requirement for daily use, the extreme conditions of a beach environment—where UV rays reflect intensely off both the white sand and the water—make SPF 50 the ideal sweet spot. Stepping up to SPF 50 blocks roughly 98% of UVB rays, giving you a crucial safety margin against the inevitable spots you might apply too thinly.