He boarded the train at about 11.30am to ride the entire 34.5-kilometre stretch from Khai Rai intersection in Nonthaburi to Min Buri district in eastern Bangkok.
The line, which covers 30 stations, will be open to public from 6am to 8pm for free daily from Wednesday until December 18, when the operator will start charging fares of between 15 and 45 baht.
The service opened to the public on Tuesday from 3pm.
The operator, Northern Bangkok Monorail Co Ltd (NBM), said the timings for free rides from December 3 to 17 will be adjusted and the public will be informed accordingly.
The Pink Line monorail is one of the feeder lines for linking people in Nonthaburi to other main electric railway systems in the capital.
The Mass Rapid Transit Authority of Thailand (MRTA) and NBM are also constructing an extension of the line from Si Rat station to Muang Thong Thani to serve residents in Nonthaburi’s Pak Kret district.