Rikido and Koji are often seen together and are partnered with each other during the Battle Trial Arc. They both joined Team Hagakure during the Cavalry Battle in the Sports Festival Arc.
They were paired up together in the final exams against Ken Ishiyama and they got along as a team, despite both failing the exam.
When the students moved into dorms, Eijiro was surprised at Rikido's cooking talents and jealous at the popularity Rikido was getting for baking a cake and enjoyed the cake.
Rikido and Hanta seem to be friends and to be good friends. They also seem to work very well as heroes and support their friends when needed. In fact they carried an injured Thirteen and helped their classmates defeat Kurogiri during the U.S.J. Incident. They helped Ochaco Uraraka during the second part of the Provisional Hero License Exam using their quirks to free civilians from debris. Most importantly, they had a key role in the Joint Training Battle/Round Four aiding their classmates with Rikido's power and Hanta's tape-support. They even celebrated together when their team won.
During the events of the I-Island Incident they were seen having dinner together and sharing a hotel room, implying they are friends.