Launched in June, the station currently broadcasts a predominantly Britpop-based schedule on DAB in London and other parts of the country, as well as online and on Sky.
From this week, Absolute 90s will be made available on the national DAB platform, Digital One, for a five-week trial period until September 30.
The station will become Absolute's fourth national digital radio service - joining Absolute Radio, Absolute 80s and the Red Button-style service, Absolute Radio Extra.
Speaking to The Guardian, Absolute Radio chief executive Donnach O'Driscoll said: "We believe in a digital future for radio in the UK.
"This trial will expand the reach of Absolute Radio 90s and give consumers ever more choice and the ability to listen to yet more unique, premium content digitally."