This is one of the most frequently asked questions. Trenitalia is always quite late publishing their timetables, this time for the period starting on 12 June (summer timetable). For long distance trains, the summer timetable is already on the Trenitalia website and it will take a few more days for it to appear elsewhere. For regional trains, it may take until next month.

Once they show up on the ÖBB website, that's currently the best place to book Italian day trains (using these steps), since ÖBB don't charge a booking fee.

I appreciate that next years timetables will not have been published yet so I’ve been doing an experimental plan based on travelling in June 2022 (only 2months away) and still the High speed trains between Geneva and Florence aren’t showing on the Interrail planner.

On which date? Any planner other than Trenitalia's own one currently only contains timetables until 11 June and is waiting for updates from Trenitalia. If any train until 11 June is missing, then it's because it's a recent update that hasn't been received yet from Trenitalia.

In addition, if you’re using the rail planner app, please be aware that it is an offline planner that does not get enough updates to be reliable: only every few weeks instead of twice per week for online planners. This app should therefore not be used to plan.

Ohhh, Now I get it...the new timetables come out on 11th June. Sorry, this is the first time we’ve done anything like this...probably should have done it in our 20’s not our 60’s 

No, because then there were NO such superfast trains.

Also note that NO hi-speed runs between Geneve and Milano-only from there. But then the views over lake Geneve and in the Rhone valley are much better!

Those ´frecce=hispeed trains run at least ev hr Milano-Firenze-Roma, only the min. after the hr may change a little.