Rice, 20, was capped three times by Ireland, but all of his appearances were in friendlies, which allows him to swap his global allegiance to the country of his birth.
The 20-year-old added that he had reached this conclusion after discussions with those two global managers, with the former Republic of Ireland manager Martin O'Neill and with his family and friends.
Like so many people around the world, I consider myself to of mixed nationality.
"This has been an extremely hard decision and, in all honesty, not one I ever expected to be making at this stage of my career", Rice said.
In a statement Rice said: "This afternoon I telephoned both Mick McCarthy and Gareth Southgate to inform them of my decision to submit a written request to Federation Internationale de Football Association for the transfer of my global registration from the Republic of Ireland to England". My parents, my family, my girlfriend and my closest friends. "I am truly grateful for the support I have received in leading to this decision", he said. However, I am just as proud of my family's Irish heritage and my affinity and connection with the country.
In the statement, he said that he has "equal love for both England and Ireland", which is why it taken him months to make the decision. Particularly not for a young lad who never dreamed of being in this position.
"I fully accept that some Irish supporters will be disappointed by my decision, and that everyone has different opinions in regard to the rules around global representation", Rice said.
"My pride at wearing the Irish shirt was always 100 percent genuine", he added. "Good luck to him", McCarthy said.
With England, Rice - if selected - has more prospect of qualifying for tournaments.