The latest data from the Investment Association compares with just £150m in September 2014.
Since April, when the pension freedoms came into force, the IA said that sales into pensions have even beaten those made in March, at £467m, which is traditionally a bumper month as investors seek to beat the end of the tax year deadline.
According to the IA, these fund sales were a combination of new money entering the pension system and transfers from existing pension pots.
On 19 March 2014, Chancellor of the Exchequer George Osborne announced that no one would ever be forced to buy an annuity under the new rules, which came into force in March 2015.
Heather Ferguson, investment analyst for Bristol-based Hargreaves Lansdown, said: “Fund sales in pensions have soared following the new freedoms introduced in April, which have made pensions more popular as people now have greater control over their retirement savings.”