Jordanian tourist Wael Nabil Salman Zureikat, 52, arrived in Pattaya, Thailand, with his partner but he was annoyed when she visited bars alone and left him to babysit.
He allegedly "decided to kill" their son and tied the youngster's feet to a buggy and tipped it off a pier in the 'sin city' tourist destination at the weekend.
He then tried fleeing the country.
Shocked locals this week discovered the tot floating in the sea and thought he was a "doll'.
Police arrived and recovered the body - still strapped into the pushchair before launching a manhunt for the father.
Speedboat captain Songsee Sunthornchai, 28, said: "I was taking tourists to an island and on the way back I noticed a body floating in the water.
"I saw it from far away and thought it was a doll, but when I went closer I saw it was the body of a baby and called police."
Zureikat was arrested at the Suvarnabhumi Airport in Bangkok last night while allegedly acting suspiciously and trying to board a plane.
Officers today took him on a crime re-enactment in the early hours of the morning.
Zureikat was pictured pointing to a gogo bar where he argued with his wife and then pointing to the spot on the dock where he allegedly pushed off his baby in the pram.
Officers said the holidaymaker arrived with his wife but he was annoyed that she went out partying alone after promising to look after their child.
He wanted her to babysit while he visited nightlife spots.
He then allegedly "decided to kill" his son.
Police Lieutenant Colonel Piyapong Ensarn said: "Police were notified of the body floating in the water at the Bali Hai Pier and we arrived at the scene to check.
"There was a young child between one years old and two years old who had been dead for two or three days.
"The body was examined and found that the left leg was tied to a wheelchair and found no signs of being hurt.
"The case progressed and at 10am on March 12, we co-operated with police forces to arrest the Jordanian tourist.
"He confessed to killing his son by tying him to a stroller and pushing him into the water.
"He said he had been to Pattaya many times and his wife had agreed to look after the baby. She went outside to bars to party and he did not want to stay alone looking after their son.
"He said he decided to kill the boy then try to fly home but he was captured at the airport."