The two have 303 caps between them
Ulster's Andrew Trimble and Rob Herring are to share the captaincy for the upcoming season.
Trimble is the province's most-capped player with 206 caps, and said,
"To be named as captain of my home Province is extremely humbling and this is without doubt one of the proudest moments of my career.
"We are a close-knit group of players and we are lucky to have so many leaders to call upon. Rob is a fantastic player and captain and I believe that we have a great structure in place that will allow us to deliver on the pitch."
Herring covered the skipper when Rory Best was on Ireland duty, and has made 97 appearances.
Commenting on the appointment, Herring said,
"I've been fortunate to captain the team on a number of occasions over the past season and it has been a great privilege. To be named a club captain of Ulster is an absolute honour and something that I will cherish for the rest of my life.
"To be able to share the captaincy with someone like Andrew is massively exciting, and together, with the support of the many other leaders in the squad, we can make strides to deliver the success that the players, staff and supporters strive for."
Best was appointed national team captain in January.
The season kicks off with the Pro12 match at home to Newport Gwent Dragons on September 2.