Kalibo's main pull is the Ati-Atihan festival in the third week of January — book accommodation months in advance if that is when you are coming. Outside the festival week, the town is quieter and the sights are modest: a Santo Niño shrine, a mangrove eco-park, a small museum, and the piña-weaving workshops that produce the Philippines' national fabric.
Most travellers stay one night and move on to Boracay or Bohol. That is a fair plan, but allow a half-day to walk into the old centre, see the cathedral, and visit one of the piña weavers — it will give Boracay a useful context.