I have a 10-12 hr transit in BOM connecting Intl -> Domestic. Is Nirantara the closest and most convenient option? Opinions about this place (or another recommendation)?

Niranta is the easiest, other options are close enough. But you will have to sacrifice 1-2 h of your time.

There are plenty of other airports within a few mins drive of the terminals: Hyatt Regency, ITC, JW Marriott, Hilton, etc. Depending on the time of day, you have to factor in the traffic.

Hyatt Regency has been closed due to bankruptcy/owners shut it down...

I wouldn't recommend the Grand Hyatt - as they really suck and are totally unprofessional.

The Niranta Transit Hotel was fine when I stayed there in 2019 during one of my RTW. Clean, and quiet. Note that this was before the pandemic, we found many food options in the terminal.
You can book online (then, not sure now) but we didn't. After we deplaned and got inside airside transfer aera, there was a hotel staff (English speaking) waving a hotel sign. Spoke briefly with him and he lead us to the lobby.

I have some photos of the hotel in case you are interested:

https://stefanofoto.smugmug.com/RTW-...nsit/i-dnvzZCM

Safe travel!

i always end up staying at either the jw marriott or itc....both are very close to the airport & good for a short transit....

How do you get from the airport to the hotel and back? Taxi's? Do they get huffy about the short trip?

I've looked at the Marriott on gmaps before & it looks like an easy walk from the airport. But I think I would dissolve into a puddle of sweat in Mumbai humidity if I had to do that walk with luggage in the afternoon.

i've walked but i wouldn't recommend it....

booking a prepaid taxi just before you exit the arrivals area or calling the hotel for a pickup would be the most convenient options....

The walk is possible, uber et al will also come to pick you up. Again, you lose time, stay with the Niranta.

How is the availability at Niranta? Can we book a room after arrival in BOM? With too much uncertainty around travel, I am a bit hesitant to book non-refundable hotel rooms.

I will be transitting BOM airport next week. Arriving at 22:40 at night with SWISS (so international flight) and leaving next day at with Air India at 06:00 (on code-share so single PNR).
Is Niranta a good option for this to avoid having to get out of the airport? If I book a room some rooms seem to be Airside and others not. Any advice on what to book?

Niranta is the easiest. They meet you when you come out the customs doors and take you to the landside entrance. Airside is only for international transit pax.

I've used the Niranta land-side a couple of times in recent years. I wasn't actually met by anyone - I had to get to the hotel by myself. It's easy enough, though - you need to head all the way to the right immediately after you exit the customs / baggage area, and go down one level, you'll see it easily enough.
DO NOT exit the airport inadvertently - you will not be able to re-enter without a great deal of trouble - supposedly if you have a reservation at the Niranta they will send someone to the airport entrance to get the security to let you in.

The rooms at the Niranta land-side hotel are adequate, if a bit minimalist. Most of them (perhaps all) have no windows because of the location, so it can feel a bit claustrophobic, but then again everything's neat and clean, they have the usual amenities, a big enough bed, etc. The breakfast buffet is so-so, but enough to quell your hunger pangs just before heading off on another flight.

Theoretically walk-ins are possible, but I strongly recommend making a reservation ahead of time. The last time I was there there was someone attempting a walk-in and disappointed being told no room was available for the next 8 hours.