All passengers taking Air Vanuatu domestic flights will be required to present photo identification from 1 July.
The airline introduced the policy in February but gave a six month grace period to passengers in the outer islands while the government's National ID Card programme was being rolled out.
Air Vanuatu's communications manager, Paul Pio, said he was confident most passengers would have some form of photo ID from next month.
They could use the National ID Card, the Vanuatu National Provident Fund (VNPF) card, a passport, school ID or a company card, Mr Pio said.
"We will have some flexibility when it comes to infants because they usually don't have access to those ID cards, and as well as elderly people."
Requiring photo ID prior to check-in on domestic flights was "a worldwide standard" for safety purposes, Mr Pio said.
"In the past, we had a few cases where people would purchase a ticket and then somebody else would travel on their behalf."