The lender, still 62 per cent owned by the taxpayer, posted a 14 per cent increase in profits to £448m in the three months to September 30.
Pre-tax operating profit was up 10 per cent to £961m but RBS also booked £200m in provisions to cover costs for the mis-selling of payment protection insurance (PPI) in the period.
It reflects higher-than-predicted complaints volumes following a Financial Conduct Authority advertising campaign featuring Arnold Schwarzenegger aimed at encouraging people to come forward before an August 2019 deadline for final claims.
RBS has made provisions totalling £5.3bn to date for PPI claims.
In total RBS detailed £389m in third-quarter conduct and litigation costs.
Chief executive Ross McEwan said: “This is a good performance, set against a highly competitive market and an uncertain economic outlook.
“We are growing lending in our target markets and are in a strong position to support the economy. We’re aware there is much more work to do and are fully focused on improving for our customers.”
RBS also said on Friday that it has secured approval from Dutch regulators to serve EU clients out of Amsterdam post-Brexit.
Earlier this month, RBS paid out its first dividend in 10 years after reaching a long-awaited £3.7bn settlement with US regulators over claims that it mis-sold mortgages in the run-up to the financial crisis.
It was considered the largest of a string of legacy issues that the bank is starting to put to rest a decade on from its bailout in 2008.