Pennant-Rea will be leaving his role as chairman at the end of the year, having held the role for over five years.
Royal London has announced his successor, subject to regulatory approval, will be Kevin Parry.
Parry is a senior independent director at Standard Life Aberdeen, having been appointed in October 2014 but is likely to step down from this position to take up his role at Royal London.
As one of the senior directors, he had been in the frame to replace outgoing Standard Life Aberdeen chairman Sir Gerry Grimstone but this position later went to Sir Douglas Flint.
In his career, Parry has worked as chief financial officer at Schroders and as chief executive of Management Consulting Group.
Pennant-Rea was a deputy governor of the Bank of England between 1993 and 1995 and joined the Royal London board as a non-executive director in 2012. He was then appointed as chair in 2013.
The Royal London board consists of ten people including Phil Loney as group chief executive and Andrew Palmer, chairman of Royal London Asset Management. Founded in 1861, the firm has £114bn in funds under management.