The 23-year-old Dutch international left the club for FC Basel in 2015 after three years and close to 100 appearances.
A season with Genk on loan followed in 2017, ahead of his return to Rotterdam.
Speaking to NOS upon his return to the club, Boetius said: “I always hoped that I would return to Feyenoord but I did not expect it to be so soon after leaving two seasons ago. I am happy to be back.
”I had a positive feeling about returning to the club. They are in a strong position and are also in a process that you want to be a part of.
“I have become more mature during my abroad and I feel that I have grown as a player. I was unlucky with injuries at FC Basel where I ended up playing less games. At Genk, I managed to play quite a few games within 6 months under Albert Stuivenberg and I was happy about that and I am grateful for the chance he gave me.”
He added: “I admit that the way I left Feyenoord two years ago was not great. But I have always got on well with the people at the club and we know that if we want to achieve success together we must have a good relationship in order to perform well.”