Emirates Skywards has launched a promotion offering double tier miles for a limited period.

The promotion is valid for flights booked up to and including December 3, for travel until March 31, 2019.

Bookings made with either Emirates of Flydubai (which recently joined the Emirates Skywards programme) will be eligible for the bonus, but note that is it only valid on certain fares.

Emirates’ customers must choose Flex or Plus Flex fares to be eligible, while Flydubai passengers must opt for Free to Change or Business Basic fares.

Customers must also log-into their Skywards account to register for the offer, either via the Emirates app, or at emirates.com or flydubai.com. It’s not clear whether this must be done in advance of purchasing a ticket.

In a press release Emirates said that the promotion meant that “Based on the fare type chosen and the class of travel, Emirates Skywards members may be able to able to move up one or even two Emirates Skywards tiers over the course of a return journey”.

“As an illustration, a new Emirates Skywards Blue tier member completing a return flight between London and Sydney, or New York and Johannesburg, on an Economy Class Flex or Flex Plus fare will be able to earn sufficient Tier Miles to upgrade to Silver tier through this offer. On a Business Class Flex or Flex Plus fare, the same member will earn enough Tier Miles to immediately achieve Skywards Gold tier.”