The company has replaced Sentek Marine & Trading as the biggest bunker supplier by volume.
Ocean Bunkering was listed eighth on the list, which is published annually by the Maritime & Port Authority of Singapore (MPA), for 2017.
Petrochina retains second position having jumped from 12th in 2016.
Glencore Singapore, which previously operated as Chemoil, fell from third place in 2017 to 21st in 2018.
Elsewhere, Shell Eastern Trading and Equatorial Marine Fuel Management Services swapped positions, finishing fourth and fifth respectively.
As previously reported, Bomin Bunker Oil, which placed 15th on the list in 2017 and 21st in 2016, announced its departure from the Singapore and Antwerp bunker markets in September 2018.
In October 2017, Aegean Marine Petroleum Network announced it would be exiting the Singapore physical market from January 2018.
Palmstone Marine Services, Harley Marine Asia and CNC Petroleum are understood not to have renewed their licences for 2018.
In total, 51 bunker suppliers were listed by the MPA compared with 55 in 2017.
List of all bunker suppliers by volume in 2018: