You, generally can't throw toilet paper down the toilet in Greece, although you can throw toilet paper in the trash can or bin next to the toilet.
Unlike in other countries, you generally can't flush toilet paper down the toilet in Greece,
Greece has narrow sewage pipes and older infrastructure and flushing toilet paper down the toilet in Greece can clog the plumbing and sewage pipes quickly.
So instead, when you're in Greece, you must place your used toilet paper into the small covered trash bin that is often provided next to the toilet.
Look for a bin in the Greece bathrooms, as there should be a small pedal bin next to the toilet, which you can use for the toilet paper.
And many bathrooms in Greece also feature signs and explicit notices that ask you to not throw toilet paper in the toilet bowl.
You should also never flush any other items including wet wipes, flushable wipes, paper towels and sanitary products or diapers as they must always go in the bin, even in modern buildings.
However, there are some modern exceptions for flushing toilet paper in Greece, as brand new luxury hotels or major contemporary developments sometimes have the updated wide bore plumbing, which can usually handle toilet paper, but you should always default to throwing toilet paper in the bin in Greece, unless you see a sign that explicitly says that flushing the toilet paper is okay.