We visited Vjetrenica Cave in early October 2024.  You can only visit the cave system with a guide from the site.  It opened at 10.00am and we undertook the first tour with just the two of us and the guide.  Cost is 10 Euro each and the tour take up to 45 min to an hour, with your ticket price including a visit to the museum to view artifacts that have been found in the cave and preserved in the museum for display.  The biodiversity of the cave system one of the main reasons for its inscription and it is not a visible part or your experience in the cave, however you do see an array of different cave system structures which are pleasant but not awe inspiring in itself.  In summer, which we were not there for, you can undertake a longer tour of up to 3 - 4 hours which includes a boat tour in the underground lake area of the cave.  This is not open to the hourly walking tour group to either view or undertake.  If in the area, I potentially will return in the summer to do so, but I would not specifically go out of my way to undertake.  Whilst you only tour a very small part of the cave system, you can appreciate its value in preserving and protecting.