Content Collection 1, which includes four new multiplayer maps and two new Spec Ops missions, is now available for £11.49 / $14.99.
It was first released in March on Xbox 360 for Elite subscribers, followed by PlayStation 3 in April.
The multiplayer maps consist of Liberation, Piazza, Overwatch and Black Box. Elite premium subscribers saw the release of Liberation and Piazza in January, while Overwatch was released in February and Black Box arrived in March.
Spec Ops missions Black Ice and Negotiator will take players snowmobiling to infiltrate a diamond mine and extracting hostages in India.
Call of Duty: Black Ops II was recently outed as the next entry in the military shooter series.
> Call of Duty: Modern Warfare 3 - Digital Spy's review
> Modern Warfare 3 March map pack preview
Watch the Content Collection #1 trailer for Call of Duty: Modern Warfare 3 below: