It depends on what you want from the river, but most travelers find the sweet spot is one or two nights.
- Day trip (from Ho Chi Minh City): The fastest look at the delta. You see the floating markets and orchards around My Tho or Ben Tre, but you spend most of the day on a bus and a boat, and you rarely get out at dawn or dusk, when the river is quietest.
- Two days, one night: The usual choice. You can stay in Can Tho or a riverside homestay on Cai Be, see the morning market by boat, and still have time for a bicycle ride through the villages.
- Three to four days: Worth it if you want to go further upriver to Chau Doc near the Cambodian border, where the floating villages and the Cham communities are. Most of the time goes to travel between towns, so pace it carefully.
A few things shape the choice: boat departures are early, so a homestay gives you the best light, and high water season (roughly September to November) can change which canals are open. Check whether your operator's trip ends at a port you can reach easily, because some cruises only run a stretch of the river.
For a fuller comparison of the one-day and four-day versions, see the conversation Is a Miko Cruise better for one day or four days?, where members have compared their trips.
Also discussed here:
- Is a Miko Cruise better for one day or four days?