I stayed at hotel Merville Beach just north of Grand Bay.
I had great viz deeper out and quite close in - typically 15-25 m and max viz was 60 m. I dived by boat at Coin de Mire (an island about 10 km NW of Grand Bay)
Freediving the wreck with short fins was a bit harder but I got used to them and slower descents - probably improved my dive response anyway. I filmed fishes there - got them close by using spearfishing hunting techniques(with no gun of course as spearfishing is not allowed in Mauritius).
I also dived with dolphins - whole family in the water and they loved that - I got pcis of them - we also dived shallow coral gardens which amazed the kids and even me too. Many of the boats will supply snorkelling gear (mask and fins).
A few days later when I had build up some fitness I dived the wreck of the Silver Star ( a convenient 15 minute boat ride from Grand Bay) It is a small ship lying almost perpendicular to the coast bow resting on reef and the stern on sand in 39m. I had one visit to the sand using shortfins - took me down slow 1:30 to get there but I was diving very light as well.
Currents were weak tidal movement and I was there on high tide in no current and a super 60 m viz - I could see the whole wreck from above.
Being solo I took it easy with long rests and good prep. There were a few rock salmon snappers which I filmed - footage was poor as the camera was "autozoomed" by the water pressure below 28 m - pity!
I did a no-fins dive to the wreck at 31m. Further out is a reef and it drops quickly to 60 m - this would be nice for freediving the area. I would love to stay for a month to focus on freediving only with competent back-up of course.
Watch my son Zephyr dive 11 meters - he did not look challenged if you ask me!