Best experience is in Havelock(andaman and nicobar). Even tried scooba diving out of india(Maldives), it is worth going in India in Havelock, we have full visibility of beautiful sea flowers, beautiful nature inside water.
You can try scuba at tarkarli, devbag beaches in winters when the water is clear & sunrays reach to good depths. but do a full scuba with the tanks because there they make you dive with only the breather & not the tank. the tanks are on the boat. but it's a good spot, get a little away from the coast.
Summer is an ideal time to scuba in India. This sport is mostly loved for it full connection to the waters especially during summers. Neil island a hamlet scuba spot
Corruption rock is a dive spot Netrani island on Mudreshwar popular for marine rocks
Kovalam on Trivandrum is a bonding spot with the sea
Kamdat islands Lakshadweep variety species of marine life live
Coral shark reef Pondicherry for the lovely reefs are some best spots to scuba in India.
Kindly check the above Tripoto link for more details.
Check these places for scuba diving in india. Havelock Islands (Andaman and Nicobar Islands)
Neil Island, Andaman and Nicobar Islands.
Grand Island, Goa.
Netrani Island, Karnataka.
Bangaram, Lakshadweep. My suggestions is to go for andaman & nicobar islands it would be the best place to experience the scuba diving.