Herman Alfonso played for the Palauan national team.
He hit .316 with three runs and three RBI in the 2003 South Pacific Games; he was third on Palau on hits (one behind Ty Saiske and Reagan Sidoi) and tied Sano Sakurai for 2nd on the squad in RBI (5 behind Sidoi).  In the 2005 South Pacific Mini-Games, he went 0 for 6 with a run and a RBI, winning Silver. 
Alfonso won Gold with Palau in the 2007 South Pacific Games.  He hit .280/.367/.280 in the 2011 Pacific Games, going 3-for-5 in steals. He had eight putouts, one assist and no errors. Against New Caledonia, his single off Sébastien Lepouriel with two outs in the bottom of the 9th scored Raynold Sadang with the winner. His seven hits were second on Palau, behind Melngis Uchel. He tied for 6th in the Games in swipes.