To enter Vietnam you will need a visa. Visa application forms now have the remark "All international border crossings of Vietnam". This simplifies the application process since tourists no longer have to specify exactly where they are entering or leaving. You can extend your visa generally for the equivalent of $20.00 and up USD.

There are multiple entry visas that are more expensive (USD 50 to USD 200). Extending will cost extra. Multiple entry visa's are especially useful if you would like to make a side trip to, say, Thailand, Laos or Cambodia or are living full time in Vietnam and would simply like the freedom to come and go as you please

It has been noted that Vietnam has been quite a bit more liberal than, say, Thailand on the issuance of multiple entry and longer term visas.