Alba
The ruler of Alba was King Constantine II (Constantine the Middle-Aged), who had ruled since 900 and would continue to do so until 943.
Deheubarth
The ruler of Deheubarth was King Hywel ap Cadell ap Rhodri (Hywel the Good), who had ruled since 920 and would continue to do so until 950.
England
The ruler of England was King Æthelstan (Æthelstan the Glorious), who had ruled since 924 and would continue to do so until 939.
Gwynedd
The ruler of Gwynedd was King Idwal ab Anarawd (Idwal the Bald), who had ruled since 916 and would continue to do so until 942.
Strathclyde
The ruler of Strathclyde during this time was either King Owain map Dyfnwal or King Dyfnwal map Owain, the exact year of the succession is unknown.