The 380-cst marine fuel price was assessed at $209 a tonne, a level last reached on 4 March 2005, Reuters data showed.
"It's not surprising with crude hitting new lows as well. Now we're looking if it can break the $200 a tonne mark," a Singapore-based trader was quoted as saying.
Oil prices hit their lowest since early 2009 on Monday, tracking a slump in Chinese equities, which fell nearly 9%.
Reuters said the fuel oil market itself has also been facing ample supplies due to huge inflows from the West and Middle East earlier this year.
Singapore bunker fuel sales fell 3.2% year-on-year, to 3.7mt in July, according to figures released by the Maritime and Port Authority (MPA).
The bunkering industry in Singapore is a lucrative business with more than 65,000 bunkering operations taking place every year.
Its bunker industry is a major revenue earner with the sector generating income of around SGD20bn ($15.2bn) a year.
