Chanathip was promoted to the BEC Tero Sasana first team squad by new coach Andrew Ord who had also been his youth team coach.
On 6 May he scored a last-minute goal against Thai Port in the Thai League 1, which gave BEC Tero Sasana a 2–0 win.
In early 2013 Chanathip had an offer from J.League side Gamba Osaka.
At the end of the season, he won the TPL Young Player of the Year.

In mid-October Shimizu S-Pulse of the J.League offered him a trial at the end of the 2013 season.
In late October it was reported directly from BEC Tero Sasana's general manager Robert Procureur that Bundesliga club Hamburg would give Chanathip a trial at the end of the 2014 Bundesliga season and if he succeeded he would be the second Thai player to play in the Bundesliga after Witthaya Laohakul.
Chanathip was promoted to the BEC Tero Sasana first team squad by new coach Andrew Ord who had also been his youth team coach. On 6 May he scored a last-minute goal against Thai Port in the Thai League 1, which gave BEC Tero Sasana a 2–0 win. In early 2013 Chanathip had an offer from J.League side Gamba Osaka. At the end of the season, he won the TPL Young Player of the Year.
In mid-October Shimizu S-Pulse of the J.League offered him a trial at the end of the 2013 season. In late October it was reported directly from BEC Tero Sasana's general manager Robert Procureur that Bundesliga club Hamburg would give Chanathip a trial at the end of the 2014 Bundesliga season and if he succeeded he would be the second Thai player to play in the Bundesliga after Witthaya Laohakul.
Chanathip Songkrasin