Balinese temples ask visitors to cover the shoulders and knees, and that rule applies to babies too. Nobody polices an infant in arms, but it still matters for photos and respect. A simple sarong tied loosely over a onesie works, or a lightweight, full-coverage playsuit meets the rule without extra layers. Ceremonies mean standing or waiting outside for an hour or more in full humidity, so how many layers a baby actually needs in hot weather matters more than how formal the outfit looks.
Muslin cotton is a good pick for this kind of day because it's woven loose and open, so air moves through it and dries fast if your baby sweats or gets carried through a blessing with holy water. It also softens with every wash, so even a first-wear outfit feels broken in rather than stiff against warm skin. Our clothes are double-layer muslin, pre-washed before they ship, and sewn with flat seams so nothing rubs at a hip or armpit during a long visit. If you're unsure on sizing, how muslin baby clothes should fit walks through it in more detail.
Pack a spare outfit. Temple visits in Bali often turn into a full day of driving and waiting between shrines, and how many outfits to pack per day for a baby is worth checking before you leave the hotel. Once home, wash the outfit cold on a gentle cycle and skip the fabric softener, then hang it or tumble dry on low. That keeps the weave soft instead of stiff, and any creasing that shows up after the trip is normal for this kind of cotton, not a flaw.