Most Thai embassies around the world have now shifted to evisa (including Savvanakhet)
Those days of border run are probably over. Info here -
E-Visa Application
Effective 1 January 2025, 10.00 hrs. (UTC+7), non-Thai nationals who are currently in Savannakhet Province, Khammouane Province, Saravanh Province, Champasak Province, Sekong Province, Attapeu Province and wish to apply for a visa to enter Thailand must submit their visa applications for all visa types through the e-Visa system at https://www.thaievisa.go.th/.
Certain nationals are eligible for visa exemption or visa on arrival. Check your eligibility at https://www.thaievisa.go.th/ under the heading “Do I need a tourist visa?” and https://thailandevoa.vfsevisa.com/.
No In-Person Submission of Passport and Supporting Documents.
Processing Time
The processing time for visa applications through the e-Visa system will take approximately 10-15 working days (if all required documents are complete), from the date the visa fee is paid.
Approval Notification
If the e-Visa application is approved, a confirmation will be sent to the applicant’s registered email. A copy of this confirmation must be printed as proof of a visa and to be presented to airline staff at departure or Thai immigration officers upon arrival in Thailand.
Applying for Visa - Consulate General in Savannakhet :: Royal Thai Consulate-General, Savannakhet