Full-day speedboat or conventional ferry tour visiting Phi Phi Don, Phi Phi Leh, Maya Bay (subject to access rules), snorkeling stops and Viking Cave; tours usually include lunch and snorkeling gear (tours run ~8:00–17:00).
Return to Phuket, shower at hotel then enjoy a relaxed dinner — try Chillva Market for varied street food if timing matches (evening market hours vary).
Short ferry or speedboat to Koh Larn — swim, snorkel and relax on several beaches (ferries run from Bali Hai Pier, trips typically 3–6 hours on the island).