Sadiq Khan plans to charge motorists to drive through the Blackwall and Silvertown tunnels, with the aim of raising at least £123 million per year.
The tolls will be introduced on both tunnels when the new Silvertown Tunnel opens in 2025.
Transport for London (TfL) will receive revenue from the tolls and penalty notices, which is expected to cover the annual costs of construction repayments and maintenance fees.