Monday morning was the busiest rush hour on the Tube since the first national lockdown, according to Transport for London (TfL).
Figures showed 831,000 taps in to the Tube network between 07:00 and 10:00 BST, the highest since March 2020.
There were 860,000 registered passengers on buses according to TfL - up 40% compared to last week.
Mayor of London Sadiq Khan said he was "delighted" by the increase.
Mr Khan said: "Our city - and our country - depends on London's economic recovery.
"I urge returning office workers to make the most of what our city has to offer."
Many children have returned to school this week for the start of the autumn term, impacting numbers. But TfL said the figures were in line with recent passenger trends.
Numbers are still far behind the pre-pandemic highs; nearly twice as many passengers used London Underground before the national lockdown.
Last month an average of more than 1.8 million journeys were made on the Tube every weekday - compared to 3.9m in July 2019.
In 2019-20 Transport for London earned £4.9bn from fares - 47% of its income.