Dragon Quest X has amassed around 300,000 paying subscribers since its launch in Japan on August 2.
The game has sold approximately 556,000 copies in the region since launch - a relatively small amount compared to other games in the series.
But Nihon Securities Journal (via Siliconera) has reported that 300,000 of those users are opting to go beyond the game's free-to-play offerings by forking out for the 1000 Yen ($13, £8) monthly subscription fee.
According to estimates, this will already be raking in around £2.3 million ($3.8m) per month for publisher Square Enix - not too shabby.
Sales have slowed drastically since it debuted at No.1 on the Japanese software chart, selling 420,000 units in four days on the market, but it's worth noting that Square's other major MMO, Final Fantasy XI, lacked the unit sales of previous offline entries in the series, but peaked at about 600,000 subscribers, according to Siliconera, which remains the most profitable games of the series.
A Wii U version of Dragon Quest X will release in Japan early next year. Western releases are yet to be announced.