Yes, a valid visa for each nation is one of the basic admission criteria. 

Cambodia Visa 

Travelers have to get a Visa on Arrival (VOA):

• Available at: Major international airports (Phnom Penh, Siem Reap, Sihanoukville) and certain land borders
• Validity: 30 days (Tourist Visa - T class)
• Requirements: Valid passport (at least 6 months validity), 01 passport-sized photo, Visa fee (around US$30 - $35), and completed visa application form (available at the airport/land border).

Vietnam Visa

You should apply e-Visa in advance at: https://evisa.gov.vn/

Or else, you can contact BestPrice Travel to apply e-Visa (US$ 40/person) with simple procedures and time-saving.

Most cruises last between 8 and 9 days, depending on the itinerary and number of stops. Some itineraries may vary slightly depending on the water level.

Cruises from Siem Reap to Saigon travel primarily on the Mekong River, including the Mekong Delta in Vietnam and segments on the Tonlé Sap River in Cambodia.

Major cruise stops often are Kamphong Cham, Phnom Penh, Chau Doc, Cai Be, My Tho, etc. Below are some highlights you may experience:

• Pnom Penh’s Royal Palace and Silver Pagoda
• Peaceful local villages with friendly people
• Unique floating markets in Cai Rang
• Majestic Sa Dec’s temples and pagodas
• Fascinating cultural performances on Tan Phong Island
• Interactive handicraft workshops in Can Tho

Here are some of the most recommended Siem Reap to Saigon river cruises with great services and the best rates (price excludes transfer fee).

• RV Mekong Navigator - From US$ 2,219/pax: Luxurious lounge, bar, and La Vie spa.
• Heritage Line Jahan - From US$ 2,604/pax: Premium services and resort-like amenities.
• Heritage Line Jayavarman - From US$ 2,403/pax: An aesthetic floating art gallery.
• RV La Marguerite - From US$ 1,756/pax: Refined design and opulent facilities.
• RV Mekong Prestige II - From US$ 2,300/pax: Spacious sundeck with a large plunge pool.

A Saigon to Siem Reap cruise typically costs between US$ 1,514 and $2,604 per person, which is about US$ 190 - 326/day. It can vary depending on the cruise line, cabin type, and season.

Yes, most tours of the attractions in the mainland are easy, but some walking is required. There are also some cycling tours that are optional. Guests with mobility issues should inform the cruise company beforehand.