Earnings after taxation hit £392 million ($518 million, 441 million euros) in the three months to the end of September, RBS said in a results statement.
That marked the group's third successive quarterly net profit and contrasted with a loss of £469 million in the same period of last year.
Edinburgh-based RBS, which is 71-percent owned by the taxpayer, signalled that it was moving on from its troubled past.
"Our strategy to deliver a simpler, safer, customer-focused bank, is working," said Chief Executive Ross McEwan .
"We have grown income, reduced costs, made better use of our capital and continued to make progress on our legacy conduct issues.
"Our core bank continues to generate strong profits and we remain on track to hit our financial targets."
So far this year, RBS has stripped out £708 million in costs -- and remains on track to reach its £750-million target for 2017.
The stricken lender was rescued with £45.5 billion of taxpayers' cash during the global financial crisis in the world's biggest banking bailout.