The clothes hangers with the pants clips - tack those curtains together and don’t forget the do not disturb sign!

I always used to be upset about inadequate hotel curtains until I started taking a sleep mask on every trip. Absolute game changer. And ear plugs, of course.

Sauron: Frodo, get up. It's a glorious new day!

I can usually get them to close tight by tugging enough on the entirety of each curtain so that they 'want' to bunch together in the middle. I hope that makes sense. This trick may not work with all of them.

The trick others have posted with the hangers that have clips is very clever, I'll definitely keep that in mind. Some hotels have hangers that you can't take off of the clothing rod, however,

That's why i always travel with electrical tape, it solves tons of problems. With curtain cracks i just overlap the curtains an inch and then tape them together that way.

Don't you just keep overlapping from one side or the other unill they don't come apart? Like overlap the curves from one side to another, sometimes takes a few tries. Though I guess air flow may impact it but the curtains are heavy and air flow is usually gentle. That's how I deal with all curtains when I want it dark. Not just a straight close.