How to get vietnam visa to cross the border between Cambodia and Vietnam ?

Hello, I’m French of nationality and living in the UK. I’m writing to find out how I can obtain a visa if I’m crossing the border between Cambodia and Vietnam. I have looked on-line and it looked like I needed to arrived at an airport.
Could you tell me what I needed to do.
Thank you.

In General Questions,Transit visa , Asked by Jérémy David Pénelet,

Dear Jérémy David Pénelet,

Thank you for your email.

This is to inform that visa on arrival is only applicable for air travellers to Vietnam. Since you plan to enter Vietnam by land, you are advised to go to the nearest Embassy/Consulate of Vietnam aboard to apply visa in person. Kindly contact them for detailed procedure and fees.

Here is some contacts for your reference.

Embassy of Vietnam in United Kingdom

Add: 12-14 Victoria Road, London W8 5RD

Tel: +44-2079371912/2075652214/+44-2079375628

Fax: +44-2075653853

Email: [email protected]

Embassy of Vietnam in Cambodia

Add: 440 Monivong Blvd, Phnom Penh, Cambodia

Tel: +855-23-726.274

Fax: +855-23-726.495

Email: [email protected]

Consulate of Vietnam in Cambodia