Rangsan Viwatchaichok

Rangsan Viwatchaichok is a Thai professional football manager and former professional footballer who is currently the head coach of Thai League 1 club Chonburi.
Rangsan currently holds the record for the most all-time appearances in Thai League 1, with 440 appearances. He is known for his set pieces freekick back in his playing career.

International career

Rangsan has played 29 games for the senior Thailand national team since 2004, and he has scored one goal in the process.

On 11 July 2013, BEC Tero Sasana sacked René Desaeyere and promoted Choketawee Promrut to be the club interim manager. Rangsan, who was the club captain, was also promoted to be the assistant coach.
On 9 August 2015, Rangsan was promoted to be the interim manager of BEC Tero Sasana after the removal of Kenny Shiels.
He had coached the club for three games before the appointment of Manuel Cajuda on 27 August.
On 1 December 2015, he was promoted to be the interim manager again after the resignation of Manuel Cajuda. Rangsan managed the club in the last three games of 2015 season with the record of 2 wins and 1 loss. The club set to relegate to Division 1 according to the final standing but still remained in top league after the withdraw of
Saraburi from the competition.

On 17 April 2017, Rangsan was appointed as assistant manager of Suphanburi under manager Adebayo Gbadebo.

On 23 April 2018, FOX Sports Asia reported in an that Rangsan was appointed head coach of Police Tero following the departure of Englishman Scott Cooper. On 29 June, he was demoted to assistant under Totchawan Sripan before getting promoted to manager again on 14 September the same year.

After 5 years at Police Tero, Rangsan was appointed to replace Surapong Kongthep as the manager of Thai League 1 club Port on 8 November 2023.

On 28 May 2025, Rangsan was appointed manager of Thai League 1 club Muangthong United replacing Gino Lettieri.

On 13 November 2025, Rangsan was appointed manager of Thai League 1 club Chonburi replacing Teerasak Po-on.

No.	Date	Venue	Opponent	Score	Result	Competition
1	18 July 2009	Nonthaburi, Thailand		2–0	4–0	Friendly

;BEC Tero Sasana

;Krung Thai Bank

;Buriram United

;Police Tero

Individual