Regional trains travel within an Italian region or between neighboring Italian regions, and are subsidized by local government at the regional level by "Contratto di servizio".

Regional trains stop at more stations than other long-distance trains, and some stop at all stations.
Regionale veloce (fast regional train) are trains stopping at about half of stations.

There are no reservations for regional trains, and for this reason, there is no price advantage to acquiring regional tickets in advance online.
Once bought, tickets for regional trains have to be validated at the station before departure. "
Validation" in this case means placing a date/time stamp on the ticket by inserting into a (usually) green and white machine either in the station or along the track.
This is because regional tickets are not for a particular date or time but are valid for a period (two months for tickets bought before 1 August 2016).
The date/time stamp is to show that the ticket cannot be reused.

From 1 August 2016, tickets are valid for the 24 hours chosen by online buyers; the date of use can be changed until the previous 24 hours of the later date.
The date of use can be anticipated until the 24 hours following this adjusting operation.
The omission about the period of use at paper shops will involve a one-way daily ticket issue.
This change aims to hinder fare evasion.

There are no discount schemes available for non-residents of Italy on regional trains.
Regional trains travel within an Italian region or between neighboring Italian regions, and are subsidized by local government at the regional level by "Contratto di servizio".
Regional trains stop at more stations than other long-distance trains, and some stop at all stations. Regionale veloce (fast regional train) are trains stopping at about half of stations.
There are no reservations for regional trains, and for this reason, there is no price advantage to acquiring regional tickets in advance online. Once bought, tickets for regional trains have to be validated at the station before departure. "Validation" in this case means placing a date/time stamp on the ticket by inserting into a (usually) green and white machine either in the station or along the track. This is because regional tickets are not for a particular date or time but are valid for a period (two months for tickets bought before 1 August 2016). The date/time stamp is to show that the ticket cannot be reused.
From 1 August 2016, tickets are valid for the 24 hours chosen by online buyers; the date of use can be changed until the previous 24 hours of the later date. The date of use can be anticipated until the 24 hours following this adjusting operation. The omission about the period of use at paper shops will involve a one-way daily ticket issue. This change aims to hinder fare evasion.
There are no discount schemes available for non-residents of Italy on regional trains.
Trenitalia