Monastery attire question- skirt

We visited the monasteries at Meteora last summer. Yes, the skirt (It's beautiful!) should be OK. They made sure all females were wearing a skirt. Even if a female had long pants on, they had to put a paper wrap or shawl over the pants. They were picky about having a skirt past the knees, but I did not see anyone questioning any slits on the sides of skirts. Don't take large steps so no one notices and you should be fine! Enjoy your trip! Meteora was impressive!

If you’re concerned, could you perhaps partially sew up the slit (temporarily or permanently) so it doesn’t show any knee?

It has been a number of years since I was in Meteora but from what I remember a number of people on the tour did not meet the dresscode. One had on long loose pants and had to wear a wrap they provided. I had on a broomstick skirt that went to above my ankles. I find them to be great for travel and cool in the heat. I am not sure that skirt you posted would be ok. But it has been over ten years since I went so things may have changed.

That's a nice looking skirt. What I'd do when visiting churches/monasteries is get a pretty little rhinestone (or otherwise decorative) pin to hold the slit closed below the knee. Then you wouldn't have to worry about the knee showing.

I was there in May this year. I only entered 3 monasteries and they were not consistent. I had a dress and my own large wrap around scarf. I was fine for 1 and the other two again had fabric to use (but they did want me to use theirs as opposed to mine 🤷🏻‍♀️). I do think this skirt would be acceptable, but if not, they will provide something.

What about safety pins to close the slit while visiting the monastery?

I would think it would be fine but you could rotate the skirt so slit is in back for good measure. I was there last summer and wore a wrap around black skirt.