The aim is to reduce waste by encouraging consumers to re-use existing chargers when buying a new device.
All smartphones sold in the EU must have USB-C chargers, the proposal said.
Apple has warned such a move would harm innovation.
The tech giant is the main manufacturer of smartphones using a custom charging port, as its iPhone series uses an Apple-made "Lightning" connector.
"We remain concerned that strict regulation mandating just one type of connector stifles innovation rather than encouraging it, which in turn will harm consumers in Europe and around the world," the firm told the BBC.
It added that it aims to make every Apple device and usage carbon neutral by 2030.
Most Android phones come with USB micro-B charging ports, or have already moved to the more modern USB-C standard.