You may request mileage credit for past, eligible transactions up to 12 months from the transaction date. Transactions prior to your enrollment date are not eligible for mileage credit.

12.9. Mileage and Tier Points which are not tracked automatically at the time of travel may be credited later at British Airways' discretion. Members may claim Mileage and Tier Points after completion of their travel either online at ba.com or if required by submitting the retained segment of the boarding pass and passenger receipts provided that the Member was enrolled in the Executive Club at the time of travel and the claim is made, within 6 months of the date of travel or the relevant transaction. A new Member may claim Mileage and Tier Points for eligible British Airways flights taken up to 3 months prior to the commencement of their Membership.

9.1.2 A Member may earn Points only in relation to:

(a) Eligible Flights taken after the Member's enrolment date and up to 30 days prior to that date; and
(b) eligible transactions (acquisition of goods or other transactions) entered into after the Member's enrolment date.