Please recommend a good dive charter and locations to consider.
Besides Lahaina Divers - who would be a good option for you both based on dive count - there's also Extended Horizons, Hawaiian Rafting Adventures or Maui Pacific Divers - all have a boat in Lahaina Harbor. LD has the biggest boats and also the most divers typically - I think they'll take 28 max - their boats are 46' Newtons with upstairs decks so it's not overly crowded. You might be there at a good time anyway since school is probably starting so less tourists. I've been on one of their boats once with 7 other divers but it was one of their advanced West Lanai Drift dives.
But they segment by experience level and there's a DM in the water with every group - no more than 8 divers max is HI law. All are going to dive Lana'i daily, Lahaina Divers sends one of their boats every other day to Molokini also. As mentioned above, some of their departure times are almost civilized since they don't need to worry about the tradewinds as much as the smaller Kihei boats do.
Just generalizing, Extended Horizons might be a more advanced crowd, IDK Hawaiian Rafting at all but Maui Pacific might be an option for you also. Besides Lanai they dive Mala Pier also and have a smaller boat so probably limit their divers to 6-8 max. I've never dove with them but have seen them in the harbor.
You both could do the Cathedrals off Lana'i if your GF is comfortable in the water. I'm pretty sure the entrance to Cathedral 1 is 50'. IMO it's the more dramatic but less fishy. Except for the big school of Moku (squirrelfish) hiding in one of the side chambers. Bring a light just for that. Cathedral 2 is more open - more collapsed so you can see more daylight.
You both could easily do most of the Lana'i coastline dives, just not the West Lanai Drift that Lahaina does as that's fast and they'll want to see experience/AOW for it. Since you mentioned Mala (pier - not harbor) Lahaina Divers also does that at night off their boat to facilitate easy entry. The legal shore entry to Mala requires navigating around shallow coral heads (mostly walking) - the easier illegal entry is across the boat channel and will get you a ticket if the authorities see you. Also you/guide are required to tow a flag.
Two other options for boat dives are the Maui Dive Shops except they keep their boat in Ma'alea just north of Kihei and feed divers to it from all their locations so it can be pretty crowded. There's also Maui Scuba Diving Center in Lahaina but the two boats shown on their website aren't theirs - they book you onto Extended Horizons or Maui Diamond II - also in Ma'alea. So you may as well book direct. What I find deceiving is that someone photoshopped out the boat names in their pictures - I'm not a fan...
If you did want to drive south to Kihei then run over to Molokini from there(shorter boat ride), B&B is probably one of the better choices for your exp. level.
Two other easy shore dives/entries in the Lahaina area are Old Airport and Kapalua Bay. Old Airport is shallow a long way out but there's some interesting remnants of the sugar loading operation almost straight out/south of the beach. Go real slow and look in any of the openings and you'll likely find octopus - even during the day. Kapalua Bay is about 40' max across the whole bay and there's not a lot of reason to go deeper. It's also one of the top beaches on Maui. Some might recommend Olawalu also but very, very infrequently you get to watch a Tiger have his turtle soup there. So that puts some people off...I think it's the only dive on Maui with a permanent shark sign.
I also recommend Tim Rollo at Tiny Bubbles also regularly. They're at one of the Ka'anapali resorts now so a good shore dive with them could be Black Rock. Since there's a golf course and the Sheraton there you have to know where to drop gear and park to save a long carry. A lot of people enter on the north side, let the current (mild) take them past the Black Rock cove then continue south and exit on the Sheraton Beach. If you do it right, leave a car at the parking garage just south of it and walk back to the enter point.
In addition to the visibility mentioned by the previous poster, another re-assuring point for new divers is that the viz. off Molokini frequently exceeds 200' so you'll see the boat anytime you're near it - or at least a boat - there's going to be several moored nearby.
have a good trip, I like Maui in the fall just about the best. Heat/Humidity/masses of Tourists are all diminished.
