Is the water cold for swimming in Bali (Nusa Penida boat trips, waterfalls like Sekumpul)?

At both Melasti and Padang-Padang beaches the water felt equally icy cold — one traveler only dipped in briefly at Melasti and didn't even enter the water at Padang-Padang, just wet her feet (for reference, she considers 28-30°C comfortable).

While snorkeling in Amed, the water felt quite comfortable for swimming — it was only slightly cool getting into the water from the boat, but swimming itself was fine even for someone who normally feels cold easily.

At Sekumpul waterfall the water is cold, but the trail itself is safe — stairs and railings are set up everywhere, and the shallow river crossing has a very weak current. Flip-flops or crocs are enough, no need for sneakers. If riding a scooter there, bring a warm layer since the area is cooler than the coast.

At one of the spots people do swim, but not everyone goes all the way in — one traveler only waded in waist-deep and didn't risk fully swimming.

Nusa Penida is chosen specifically because you can actually swim there (unlike some other spots), so it's worth bringing everything needed for a swim.

At the dive/snorkel point the water is cold, and travelers often ask about the total duration of the trip from shore to shore when going with a group.

This spot isn't ideal for swimming — waves stir up sand from the bottom, making the water murky.

The water is cold enough that even people hoping to swim laps for distance sometimes don't feel like getting in.