Disclaimer: I did not visit Sundarbans. I thought of visiting and studied available options. I met tour operators in Kolkata who organize Sundarban tours. Eventually I decided NOT to take the trip. This post might only helps you in planning your Sundarban visit from Kolkata based on my observations and analysis.
When I was planning my Kolkata trip, one of the prospect was to visit Sundarban. Sundarban is a mangrove forest area, some 100kms from Kolkata. When I googled, two main operators emerged- one was by West Bengal tourism, who had different packages with stay in a house boat, prices starting Rs 4300 onwards. But they had once in a week fixed departures which wasn't very convenient to me. Next was a website called Sundarban Chalo. Their website seemed decent and so is the service. I spoke to them on phone- I was told price mentioned on the website is all inclusive. Then sent an email detailing my needs. But I didn't get any reply for the email, so I didn't bother booking anything in advance.
Once in Kolkata, I was still in half mind whether to visit Sundarban or not. I've already seen Mangrove forests in Pichavaram, south Tamil Nadu. Since Sudder street, where Sundarban Chalo office is located was walkable from our hotel, we walked to Sudder street and found their office. It was a super small office (see pic). We were asked to take a 2 day trip at Rs 4000 per person, instead of one day trip that I was interested in. (Couldn't afford to spend 2 days at Sundarbans).
From the itinerary, it sounded like 2 day trip is waste of time. It starts late, half time is lost in city travel itself and same thing that can be seen in a day is split into 2 days with a night stay thrown in.
2 Day/1 night
Rs 3000 per person for group of 4+, Rs 4500+ per person for smaller groups
Rs 4000 per person
Start time from Kolkata
6AM (stated, could be delayed))
8AM (stated, could be delayed)
Approx time of reaching Sundarbans
More city traffic
Activities at Sundarbans
Boat ride in Mangrove, Visiting watch tower
1 night stay
Village tour, Sunset view
Boat ride in Mangrove, watch tower, resort activities like bonfire/music etc
4 PM day 2
Reach Kolkata by
9 PM day 2
Quick visitors who don’t have multiple days to spare
Leisure travelers who don’t mind spending 2 days in a relaxed schedule but same activity that could have been covered in 1 day
Sudder street is full of tour operators. I asked at 2-3 other operators and got similar quotes, ranging around Rs 10k for 2 people for a day visit. I left my number with the operator, stating that if there're other parties interested, I wish to join at Rs 3000 person rate. Didn't get any call. So I proceeded with Bishnupur visit. Sudarban will have to wait.
Also here's another Sundarban tour, 3N/4D which might be of your interest.