By boat
You will be missing a big part of Vietnamese life if you do not spend some time on a boat. Do be careful though because many boats, although seaworthy, are not designed to first world standards. An example is the ferry from Phu Quoc to the mainland. This ferry has one tiny entrance for all passengers to board. When full, which it usually is, there are approximately 200 people on board. In the event of an accident, the chance of everyone getting out of the boat fast enough would be very small. The idea of an emergency exit does not exist.
Tour boats can be chartered for around US$20 for a day’s tour; but beware of safety issues if you charter a boat. Make sure the boat is registered for carrying Tourists and has enough life jackets and other safety equipment on board. Or you can book a tour through a tour company; but be aware that in Vietnam most Tour Agents charge whatever markup they want and therefore the tourist is often paying margins of 30-40% and the boat owner and operator (of anything from a van to a boat) are paid very little of the total amount!
Ha Long Bay is a famous destination for 1-3 day boat trips among its scenic limestone islands. Problem is that all the boats seem to visit the same places - and with high prices and poor quality boats and service real value is hard to come by! Many boats have a US$10 corkage fee, and forbid BYO alcohol, with on board alcohol and seafood about the same price as Europe on some boats! If there is rain, mist or low cloud, you may not see much. Try to pick a clear day.
Dozens of small family-operated boats ply the river in Hue taking visitors to the imperial tombs southwest of the city. This journey is long because the boats are slow, taking about 4 hours or so to make the journey in one direction.
Snorkel - fishing - lunch trips are available from Nha Trang, Hoi An, and Phu Quoc to nearby islands. In Central Vietnam, the North East monsoon season limits many sea boat tours during the months Sep-Feb; other parts of Vietnam seem less affected.
A 90-minute hydrofoil boat operates from Saigon to the seaside resort of Vung Tau for about 120,000 dong each way — the fastest way to reach the beach from the city.
River tours are perhaps the most interesting. A day-long boat trip forms the core of almost any tour of the Mekong region.
ABOUT CRUISING IN VIETNAM
text from http://www.vietnamonline.com/transport/vietnam-cruise.html
Cruises in Vietnam contain 3 main types: International cruise, Premium Cruise and River Cruise. Cruises are new form of travelling in Vietnam so they are not as widely popular as other forms of transportation. However, with just a little more research, you will find yourself an attractive cruise package that will give you a unique perspective on the destinations.
International cruise
Vietnam is a favourite international cruise destination when you are on a Southeast Asia cruise. There are many cruises, coming from various locations, that dock at Phu My, a commercial port on the South China Sea near Vung Tau, about 2.5 hours’ drive from Ho Chi Minh City. This dock provides some basic facilities besides the nearby resort complex in Vung Tau which can be reached by bus or boat.
In order to explore Ho Chi Minh city hustle, most international cruises provide shuttle bus to the city centre, near the Rex Hotel, where you can visit the various historical and attractive sites in the city on foot or by taking a cab.
Recently there are also international cruises that travel from Hong Kong (Star Cruise) or other parts of the world (Millennium and Celebrity Cruise) that dock in Halong Bay, at Cai Lan port. From here it is easy to take a taxi to get to Bai Chay or Tuan Chau pier to board a smaller junk to visit the Bay or to visit further inland.
Premium cruise
If you are already staying in Vietnam and want to take a cruise trip, you can also find affordable cruise package that provides exceptional service. Halong Bay cruise normally provides a 2 day-1 night or 3 day 2 night package tour. Depending on the level of luxury you prefer, you can find information about these cruises from local travel agents, easily found in the Old-quarter.
Though scanning through company’s website is convenient, the price is usually at ‘starting price’ and of top-of the list price. It would be much more informational and better for your wallet if you go directly to travel agents and negotiate for a lower price. This will help you find the most suitable package for you and have a sense of ‘discount’ on a deal. A typical 3 star cruise to Halong Bay costs about $80 which provides bus service to the dock, swimming, kayaking, a visit to Surprising Cave and various islets in the bay.
If you think staying on the cruise in the evening is boring since most visiting activities stop after the sky is dark, you will have to think again. You can try your luck in mid night fishing or sing your heart out in the on board karaoke session.
River Cruise
Being a country rich with natural water ways, you cannot miss a chance to go on a river cruise, especially those around the Mekong Delta in the South. Just like premium cruise, you can find a range of quality for river cruise. You can choose to go on a cruise that visit all the wonders of the south in a 2 day-1 night trip or go a full week to visit Cambodia. On a southern river cruise, you will get to see the juicy and irresistible fruit gardens and taste the fresh fruit picking from the trees. You will also see the life of people living on the river bank and their floating market.
While Northern of Vietnam is not filled with water ways, you still can go on a day cruise on Red River or Perfume River in which you can listen to the amazing stories from the past and how the lives of the people in the area transform over the years.
Here is a list sources
http://www.indochinasails.com/en/about-us.html
http://hoanglongasia.com/en/services.php?hl=du-lich-cat-ba
http://www.emeraude-cruises.com/