Hidde is a former Netherlands Under-21 international and joins having spent the last three-and-a-half seasons with Eredivisie side FC Utrecht where he played more than 100 games.
Ter Avest started his career with FC Twente, playing exactly 100 times, before moving to Serie A with Udinese where he spent two-and-a-half years playing in one of Europe’s top leagues.
The 27-year-old now joins Oxford United for his first foray into English football and will add more top-level experience to the side.