Can I take public transport up Mount Ainslie and walk down?

Agree on a drop-off at the summit and choose your walking finish before you set out. The return to your accommodation may require another bus or car trip from the trailhead.

The summit walk is still a proper bushland outing. Check the ACT Parks track notice, distance and grade, and bring water and suitable shoes even if you start at the top.

Check Transport Canberra's current route map rather than assuming a regular bus serves the summit. If there is no suitable service, a taxi or rideshare to the lookout is the simplest downhill-only plan.