The push runs across three channels: Post Offices, NT, the National Trust member magazine and Classic FM magazine.
Consumers buying three Coastlines presentation packs at a Post Office can claim a National Trust entry voucher, and will also be entered into a prize draw to win one of five National Trust Holidays.
Royal Mail is also sponsoring a CD covermount on the Classic FM April issue, with music to fit with the coastal theme. The CD insert offers the chance to buy a mini subscription of three packs and receive the free National Trust entry voucher and draw entry.
NT's spring edition also offers readers the chance to take out a mini subscription, with the incentive of a free Coastlines Classics CD and entry into another draw.
"We wanted to introduce stamp collecting to new audiences, and felt that Trust members and Classic FM listeners shared characteristics with core collectors,
said Heather Edwards, SP manager for Royal Mail Stamps and Collectables.