Pathfinder International, a nonprofit organization dedicated to providing global sexual and reproductive health services, is expanding its offices in Watertown, said a broker involved in the lease transaction.

The broker is Cassidy Turley FHO, a commercial real estate firm with offices in Boston.

Pathfinder International has been leasing just over 23,000 square feet of space at 9 Galen St. in Watertown. A lease renewal will increase its footprint by nearly 30 percent. All told, Pathfinder will occupy about 30,000 square feet of space, Cassidy Turley said.

Some of what Pathfinder International does is HIV prevention and AIDS care in treatment. The nonprofit operates in more than 20 countries.

“We believe that the additional space will allow us to better serve key populations in the hardest to reach and most remote locations,” Pathfinder International president Purnima Mane said in a statement.

The landlord in the lease renewal was represented by Colliers International.