Heavy supplies in Asia and and cheaper bunker fuel during the month drew buyers to Singapore, traders said.
September bunker premiums, the price differential between ex-wharf bunker and fuel oil cargo values, averaged at 73 US cents a tonne, lower than August's average of US$1.51, Reuters data show.
'It's a cost issue, Singapore is the cheapest port for bunkers in the region compared to Hong Kong or China, and that remains its biggest attraction,' said a Singapore-based bunker trader.
The rebound in September comes after volumes fell in August, snapping a string of five straight months of record bunker sales.
Volumes were up even as vessel arrivals for September fell 4.0 per cent versus August.
Sales of the most common 380-centistoke (cst) grade gained 9.7 per cent to 2.79 million tonnes, but were down 11.9 per cent for the cheaper 500-cst grade at 432,900 tonnes.
Last month saw heavy cargo arrivals totalling 3.7-3.8 million tonnes, compared to 3.1-3.2 million tonnes in August.
Supply of fuel oil to the region continues to be strong, with four-year high volumes of around 3.9 million tonnes fixed for October, while November bookings were at 3.2-3.3 million tonnes.