Police spokesman Prawut Thawornsiri said a court issued the warrant based on grainy video footage of a man in a blue shirt kicking a bag into the water near the pier on the night of August 17 (local time), soon after the blast at Bangkok's Hindu Erawan Shrine.
"We issued an arrest warrant for the suspect in the Sathorn pier incident," police spokesman Prawut Thawornsiri told Reuters, referring to a pier near Bangkok's Chao Phraya river.
The suspect faces charges of unauthorized possession of explosives, exploding a bomb that could cause harm and attempted murder, according to the warrant.
The pier explosion caused no casualties.
Police have not definitively linked the two blasts and have offered few answers as to who could be behind the attacks.
In the shrine bombing investigation, police are focusing on a man seen in blurry security camera footage.
The footage shows a man in a yellow shirt and dark hair removing a backpack after entering the packed shrine and calmly walking away from the scene before the explosion.
Last week police issued an arrest warrant for an "unidentified foreign man" seen in the video footage along with an image of the suspected bomber.
Prawut said police were unlikely to issue a picture of the suspected pier bomber.
"We're unlikely to make a sketch of the suspect as his face is not clear," he said.
The Erawan shrine bombing has taken a toll on tourism and caused a 17% fall in tourist arrivals, Thailand's tourism ministry said.
Fourteen foreigners were among the 20 people killed in the attack at the famous Hindu shrine in Bangkok's bustling commercial heart.
