The 28-year-old South African only joined the Pro14 outfit last year but was restricted to four appearances because of a shoulder problem he suffered against Benetton Treviso last November.
Boshoff made what turned out to be his final appearance against Munster in May after requesting to be released from his contract to return home in order to be closer to his family following his father's tragic death.
On his departure, Boshoff told the club's website: "I would like to thank Connacht Rugby for agreeing to my request to be released from the final year of my contract after what has been a difficult season for me both on and off the field. During my time with the province I have experienced first-hand the unique sense of pride and community that exists throughout the province.
"There is an incredible group of players representing Connacht and I am proud to say I was part of this group. I have learned hugely from both players and management over the past season and this experience will have a positive impact on my career in the future."