GETTING THERE: British Air and Air India are the principal international carriers to Bangladesh. Round-trip coach fare from New York to Dacca costs about $3,000. A visa is required; contact the Bangladesh Embassy, 2201 Wisconsin Ave. NW, Suite 300, Washington, D.C. 20007, 342-8372, for more information. WHEN TO GO: The "cold" season runs from mid-October through February. At that time, days are sunny and clear, with temperatures ranging from 50 to 70 degrees Fahrenheit. The "hot" season, from March through May, gets into the high 90s with humidity also in the 90s. The monsoon usually begins by mid-June (although it was considerably later this year), and lasts into October. GETTING AROUND: Boat travel predominates, and is both safer and more pleasant than land travel. An overnight ferry from Dacca to Barisal takes 12 hours. First-class is popular; book in advance, if possible.

Bangladesh Inland Waterway Transport Corp. (BIWTC) operates launches and ferries on all major river routes. For more information, write to the national tourist office: The Bangladesh Parjatan Corp., Old Airport Building, Tezgaon, Dacca 15. There is also an office at the Dacca Sheraton Hotel.

Biman Airlines, the national airline, serves the cities of Bangladesh and also offers service to other Southeast Asian countries.

Train travel is said to be less crowded and class-conscious than in India, although the trains we saw appeared overwhelmed with passengers. Also, because of the many rivers in Bangladesh, many of the train routes are quite circuitous.

If you choose to travel by road, a car and driver can be hired through the tourism office or through the Sheraton or Sonargaon hotels. A car without air-conditioning cost me about $16 a day. HOW TO DRESS: Cotton is the cloth of choice. Women should wear long sleeves and long skirts when possible. Loose-fitting pants are tolerated, but may be considered suggestive in remote rural areas. Shorts should not be worn. Hats are essential, especially in the hot season. HEALTH: Typhoid, tetanus, diphtheria, cholera and gamma globulin injections are recommended, as are malaria pills. FOOD AND DRINK: Don't drink it unless it's in a bottle, period. Bottled water, sodas and beer are available in Dacca. Bottled U.S.-brand sodas are available throughout the country, although it's very rare to find them cold. Tea is commonly available, and is generally safe if the water has actually been boiled.

Alcoholic beverages are available in the hotels, but not on Fridays, the Muslim holy day. If you bring your own bottle of liquor to the dinner table, as I unwittingly did one Friday, expect to be reprimanded or asked to leave.

The best and safest beverage is coconut milk. Vendors lop the top off a green coconut and insert a straw; several ounces of clear, slightly sweet liquid will refresh and rehydrate you nicely.

Chicken is quite good in Bangladesh. So is shrimp, where available. So is hilsa, the native fish. Try to get food that has just been cooked and is still warm, although that isn't always possible. Cardamom rice is common, and good. Yogurt is sometimes available. The summer is mango season, and the sweet, dribbly fruit can be eaten safely after being peeled. INFORMATION: The Bangladesh Parjatan Corp., Old Airport Building, Tezgaon, Dacca 15, is the national tourist office. "Bangladesh: A Travel Survival Kit," by Jose Roleo Santiago (Lonely Planet Publications, 1985), is an especially helpful guidebook.