Amazon is differentiating its video service by enabling customers to download content to watch offline.
Subscribers with iOS and Android devices can now watch TV and films without an internet connection for no extra charge.
The digital company noted how rival online subscription streaming video services, notably Netflix, did not offer this service.
Amazon does not share customer numbers for any of its services.
Its Instant Video service began life in 2006 and is now available in the US, the UK, Japan, Austria and Germany.
Amazon Prime customers in the US, the UK and Germany get Instant Video as part of their annual subscription.
The company has been investing heavily in developing its own content in recent times.
This summer, it revealed it had signed up former Top Gear presenters Jeremy Clarkson, Richard Hammond, and James May to work on a new series due for release in 2016.
Michael Paull, Vice President of Digital Video at Amazon, said: "There's no doubt that the way people watch entertainment is changing – anytime, anywhere viewing is important and we are excited to provide our Prime members with offline viewing capabilities on iOS and Android platforms starting today.
“We are proud to be the first and only online subscription streaming service that enables offline viewing – on vacation, in a car, at the beach, on a plane, wherever our Prime members want to watch they can, regardless of internet connection.”