Lisbon, Faro, Porto and Funchal have implemented the technology to make entry into the country "quicker and smoother".
British passengers using them will no longer need to queue in conventional passport control lanes, although they will still be required to go through a passport stamping process.
Gatwick, which has more than 260 flights a week scheduled to and from Portugal this summer, welcomed the move.
EasyJet will operate most flights between Gatwick and Portugal for the summer season, followed by TAP, British Airways, Wizz and Tui.
