One honest day in Alleppey needs one decision: water in the morning or water in the afternoon. The version below does both without rushing, starting near the canals and ending at the sea. Alappuzha guide →
Morning: shikara or canoe through the paddy canals before the day boats start — an hour or two is enough to understand the backwaters. Breakfast in town (appam and stew is the local default), then the market quarter or the museum if you want culture with your coffee.
Afternoon: board a half-day houseboat for the sunset run — the circular loop or the lake front depending on your board point. Tea and snacks on deck as the light goes. Evening: Alleppey Beach for the pier silhouette and the food carts.
If this is the only Alleppey day of a Kerala trip, swap the afternoon for a full-day Kuttanad cruise with lunch on board — you'll see more water in one go. The planner maps the day's legs.