For warm weather, bring cotton, linen, and any other natural-fiber clothing that allows your skin to breathe and is easy to wash. You can get your laundry done very inexpensively (a dollar a kilo) at shops and stands outside most hotels, although you may not want to give them your delicate items. Pack a light raincoat or umbrella during the rainy season and warmer clothing in winter and early spring, if you are traveling the length of Vietnam check the climate for each region as temperatures vary hugely. Dress in Vietnam is generally informal, except during meetings. Shorts are acceptable for both men and women, although women may feel more comfortable in longer shorts or skirts.
Sandals, nylon or canvas sneakers, and walking shoes are fine for the cities and more developed parts of the country. Hiking boots are recommended if you're going to head into the hills or onto trails or if you are traveling during the rainy season. Keep in mind that you must remove your shoes when entering most temples, so you may want to bring ones that are hassle-free. A hat and sunblock are always good ideas.
In your carry-on luggage, pack an extra pair of eyeglasses or contact lenses and enough of any medication you take to last a few days longer than the entire trip. You may also ask your doctor to write a spare prescription using the drug's generic name, because brand names may vary from country to country. In luggage to be checked, never pack prescription drugs or valuables. To avoid customs and security delays, carry medications in their original packaging.
Pack mosquito repellent and a first-aid kit (with, perhaps, antacids, antidiarrheal, cold medicine, Band-Aids, and antiseptics). Other items to consider are a Swiss-army knife, prophylactics, feminine hygiene products, packs of tissues (toilet paper is not always supplied in public places), moist towelettes or liquid hand sanitizer. Diapers and baby formula are available in Vietnam, but you may not be familiar with the brand and they are surprisingly expensive; unless space is tight, it’s preferable to bring your own.