Users who have registered the system with the Club Nintendo service since November will receive one free game download from today.
Titles include New Art Academy, Super Mario 3D Land, New Style Boutique, Professor Layton and the Miracle Mask and Freakyforms Deluxe.
The promotion is available to all 3DS XL owners, even those who purchased the system before the promotion started, and will continue until January 15.
The code will be sent to registered Club Nintendo email addresses and must be redeemed by January 31.
Nintendo recently released the Pikachu-themed 3DS XL, alongside a number of new retail bundles for its latest handheld.
The "extremely limited" Pikachu edition 3DS XL launched earlier this year in Japan and features Pikachu's face emblazoned on the outer casing. It will be available to purchase from December 7.
Mario Kart 7 and Super Mario 3D Land bundles, meanwhile, will be available by the end of November.
Watch a trailer for Super Mario 3D Land below: