They'll face Kilmacud Crokes who were comfortable winners over Portarlington.
The Downs are into their first Leinster final in 50 years.
Lar Wall's side edged past Ratoath by 2-12 to 17 points.
Luke Loughlin starred for the Westmeath champions hitting five points, the dual code man was named player of the match in Saturday's first semi final.
They'll face Kilmacud Crokes who enjoyed a comfortable 1-12 to 4 point-win over Portarlington at Croke Park.
Loughlin says credit has to go to the side's manager Lar Wall:
CCFL: Wins For St Peter’s And Clonaslee United In Senior Division
Leinster SFC: Westmeath Boss Not Happy With Quick Turnaround
Leinster SFC: Kildare The Next Challenge For Laois
Meath Run Riot Against Laois In Leinster Minor Football Championship
Laois Host Meath In Leinster Minor Football Championship
Wins For Laois And Westmeath In Leinster Minor Hurling Championship
Leinster SFC: Offaly Suffer Eighth Defeat On The Bounce
Leinster SFC: Five First Half Goals Clinch Quarter Final Spot For Westmeath
Wexford See Off Athlone Town In First Division
Leinster SFC: Laois Earn Quarter Final Place With Win Away To Offaly
England Too Strong For Ireland In Women's Six Nations
Rory McIlroy Wins Back To Back Masters Titles
Lowry And McIlroy Set For Masters Showdown
Athlone Town Searching For Back To Back Wins In First Division
Injury Blow Puts Kielan Woods’ Grand National Ride In Jeopardy
Offaly See Off Meath In Leinster U20 Hurling Championship
Leinster SFC: Offaly Looking To Win First Competitive Game In 2026
Westmeath’s Inny FC U12s Reach Connaught Final
Aoife Dalton Named To Start For Ireland's Opener In Women's Six Nations
Opening Round Of 70 For Shane Lowry At Masters