Cap badge Prince Edward Island Light Horse
The PEIR perpetuates the following units of the Canadian Expeditionary Force:
- 1st Brigade, Canadian Garrison Artillery, CEF
- No. 2 Canadian Siege Battery, CEF
- No. 8 Canadian Siege Battery, CEF
- 105th Battalion (Prince Edward Island Highlanders), CEF
In 1946 the amalgamation of The Prince Edward Island Light Horse and The Prince Edward Island Highlanders created The Prince Edward Island Regiment, 17th Reconnaissance Regiment.
The Prince Edward Island Regiment was amalgamated with the 28th Light Anti-Aircraft Regiment in 1955.