In tropical heat, what matters most is airflow. Muslin cotton is woven in a loose, open weave, so the gaps let air move through the fabric instead of trapping heat against your baby's skin. That same loose weave makes it lightweight and quick to dry, which helps after a dip in the ocean or a pool. Muslin also softens more with every wash, and it creases easily. That's just how the weave behaves, not a flaw.
Our clothes are double-layer muslin cotton, pre-washed before they leave us so they arrive soft instead of stiff. Seams are sewn flat so there's nothing rough rubbing against your baby, and we use child-safe dyes with no harsh finishes. Sizes run from newborn up to about 4 years old. To keep them soft wash after wash, use a cold, gentle machine cycle, tumble dry low or hang to dry, and skip the fabric softener and high heat, both work against the fabric more than for it.
The outfit is only part of the plan for a beach day. Keep your baby out of direct sun as much as you can, especially around midday, and bring a hat and some shade, like an umbrella or a beach tent. Rinse off saltwater or chlorine and change into something dry once you're done swimming, since wet fabric sitting against skin for hours isn't comfortable in that kind of heat. We're Vanessa and Bob, we design from Bali, so we dress our own kids for this exact weather. We ship worldwide with tracked delivery, and if something isn't right, unworn returns are accepted within 30 days.