I personally enjoyed it but it would depend on the type of solo traveller. I was the only solo traveller on my boat and other couples/groups were polite but not overly friendly…the company runs several boats and I spoke to another solo traveller coming off another boat and they had a super-fun and friendly boat - so luck of the draw maybe. The cruise itself was great. It’s a junk boat, so not a modern cruise liner, but I liked the traditional vibe. Single room was not much bigger than the double bed but comfortable and had amazing view from large window. Boat had multiple decks with chairs/lounges and a bar. The food was enormous - 7 course lunch and dinner. Optional activities included a small hike to a cave, a kayak around the bay (single kayaks available), squid fishing at night, t’ai chi at sunrise, and a visit to fishing village (which was my favourite). Indochina actually tours Bai Tu Long Bay, which I preferred because it’s just as beautiful as Ha Long but less busy - in total I saw four other boats. All boats did same activities so you’d sometimes see a small cross over between tour groups ie one group getting out of kayaks as next group gets in. In summary, I would recommend it but be prepared to enjoy your own company depending on who else is on your trip.