de Koning arrived in Corpus Christi in 1970, where he served as captain of the University of Corpus Christi Tarpon Tennis team. de Koning excelled on the team, which was ranked as high as No. 5 nationally under Coach Bob Mapes, the highest ranking on record for any team to date. He was also a well-rounded student-athlete, earning recognition on the Dean's List for seven of his eight semesters, and served on the student council and the cheerleading squad.

When the Intercollegiate Athletics program at Texas A&M University-Corpus Christi began competing at the NCAA Division I level in the fall of 1998, de Koning was tabbed as the head coach of the Islanders women and served in that position for nine years.