The visa and the work permit are different
A Non-Immigrant B visa lets you enter Thailand for the purpose of working. A work permit, issued by the Ministry of Labour, lets you actually do that work. You need both — and the work permit is tied to a specific employer, specific job title, and specific work location.
Change employer and the work permit must be reissued. Change job description, location or employer name and the work permit must be amended — usually within 15 days, with fines for late amendments.
The 2M / 4-Thai rule
For a standard Thai limited company to sponsor one foreign work permit, it must have:
- 2,000,000 THB of registered and paid-up capital per work permit issued.
- 4 Thai employees per work permit, all registered with the Social Security Office and on payroll for at least the minimum wage.
- VAT registration and at least one quarter of PP.30 filings on file.
Document bundle the Labour Office asks for
- Employer DBD certificate (issued within 30 days), shareholder list, VAT certificate.
- Last 3 months of PP.30, PND.1, PND.53 and SSO filings.
- Employment contract signed by both parties, with salary at or above the minimum for the foreign worker's nationality (typically 50,000 THB+ for Western nationals).
- Foreign worker's degree certificate and CV — legalised by their own embassy or notarised abroad if requested.
- Medical certificate from a Thai hospital confirming no prohibited diseases.
Renewals and timing
Work permits are issued for the duration of the underlying visa — usually 1 year. Renew at the Labour Office at the same time as your Non-B extension, and always re-do the work permit first because Immigration will want to see the renewed permit when granting the extension of stay.
Penalties for getting it wrong
Working without a permit is a criminal offence carrying fines of 5,000–50,000 THB and possible deportation. Employers face fines of 10,000–100,000 THB per illegal worker. 'Work' is interpreted very broadly under Thai law — answering business emails, attending a sales meeting, or volunteering at a friend's bar can all qualify if a labour officer decides to make the case.