Lao visa can be obtained from Lao embassies and consulates abroad; it also can be obtained on arrival at the border crossing or international checkpoint. You can get 30 days visa on your arrival or get it in Lao embassies and consulates in Australia, Belgium, Brunei, Cambodia, Cuba, PR of China, France, Germany, Hong Kong, India, Indonesia, Japan, DPR of Korea, the Republic of Korea, Malaysia, Mongolia, Myanmar, Philippines, Poland, Russia, Singapore, Sweden, Thailand, USA and Vietnam. The visa fee is USD 20 to 45 depending on your nationality.
Lao visa on arrival:
International airports
1. Wattay International Airport in Vientiane Capital.
2. Luang Prabang International Airport in Luang Prabang Province.
3. Pakse International Airport in Champasack Province.
Thailand - Laos
1. Xiangkong (Thailand)- Houaixay (Bokeo Province)
2. Nongkhai (Thailand) - Friendship Bridge (Vientiane Capital, Laos)
3. Thailand - Xayabouly Province (Nam Heuang Friendship Bridge)
4. Nakhon Phanom (Thailand)- Thakhaek (Khammouane Province)
5. Moukdahan(Thailand)- Friendship Bridge II (Savannakhet Province)
6. Chong Mek (Thailand)- Vang Tao (Champasak Province)
7. Chiangkhong (Chiang Rai, Thailand) – Houixay (Bokeo Province, Laos)
8. Nakaxeng(Loei, Thailand) – Kaenthao(Sayabouly Province, Laos)
9. Bungkan (Thailand)- Pakxan(Bolikhamxay Province, Laos) no visa on arrival.
10. Nakorn Phanom(Nakorn Phanom, Thailand) – Thakhaek(Khammouane Province, Laos)
11. Chongmek (Ubon Ratchathani, Thailand)- Vangtao( Champasack Province, Laos)
Lao National Tourism Administration-Entering Laos
*edited to include link*