In Thailand, the age of consent is 15 years old, meaning that anyone under 15 years old cannot legally consent to sexual activity. Sexual intercourse with a child under 15 is criminalized, with or without consent.
The punishment for sexual intercourse with a girl under 15 is 4–20 years in prison and a fine of 8,000–40,000 Baht. If the victim is under 13, the punishment is 7–20 years in prison and a fine of 14,000–40,000 Baht, or life in prison.
Source: https://www.siam-legal.com/thailand-law/legal-age-of-consent-in-thailand/