Before an attendance of 16,616, Jack Cooney's side shot out the blocks and had far too much physical power for younger and more inexperienced opponents.
Led by John Heslin who top scored with eight points, four from frees, and with Ronan O'Toole pulling all the strings outside him, it was effectively decided by the 14th-minute when they moved 1-4 to 0-0 ahead, their goal from defender Ronan Wallace a symptom of how poorly Offaly defended through as he went through onto David Lynch's ball unchecked.
Offaly did get back with a goal of their own on 18 minutes when Niall McNamee punted a quick free into Keith O'Neill's path and the corner-forward made no mistake.
But it was only temporary respite as Westmeath continued to dominate, building up a 2-11 to 1-6 lead at the break.
Lorcan Dolan got their second goal, combining some fancy footwork along the ground after good approach work initially from James Dolan.
And it might have been more had a Heslin goal attempt not been blocked by his own colleague Luke Loughlin on 29 minutes before Offaly full-back Declan Hogan cleared the danger.
They were much more secure at the back too with Jamie Gonoud, Kevin Maguire and Dolan all making big impacts.
Offaly got a bit of reaction off their bench with 1-5 scored, three points from Dylan Hyland and a goal from Cathal Flynn helping them to stay in touch.
But Westmeath left their best goal until last, Lorcan Dolan driving home forcefully after Maguire's initial burst on 53 minutes.
Offaly were just short too many players to make any inroads against a Westmeath team that manager Jack Cooney admitted afterwards is intent on picking up silverware.
For John Maughan, his future with Offaly is now in doubt after four years though he said afterwards that it would be a couple of days before he makes his intention clear.
Westmeath: J Heslin 0-8 (4fs), L Dolan 2-1, R O'Toole 0-4, S McCartan 0-3, R Wallace 1-0, L Loughlin 0-2, R Connellan, J Dolan, R Forde, A Gardiner all 0-1 each
Offaly: N McNamee 0-6 (6fs), K O'Neill 1-2, C Flynn 1-0, D Hyland 0-3, A Sullivan 0-2, J McEvoy, M Abbott, J Bryant all 0-1 each.
Westmeath: J Daly; J Smith, K Maguire, J Dolan; R Wallace, D Lynch, J Gonoud; S Duncan, R Connellan; L Loughlin, J Heslin, L Dolan.
Subs: R Forde for Duncan (45), G Egan for Lynam (54), A Gardiner for L Dolan (62), N Harte for J Dolan (68), K Martin for Loughlin (68)
Offaly: P Dunican; L Pearson, J Moloney, D Dempsey; R Egan, D Hogan, C Donohoe; C McNamee, J Hayes; B Carroll, R McNamee, A Sullivan; J Bryant, N McNamee, K O'Neill.
Subs: D Hyland for Carroll (22), J Lalor for C McNamee (h-t), M Abbott
for Pearson (52), C Flynn for Bryant (52) J McEvoy for R McNamee (65)
Referee: P Faloon (Down)