Yampupata is a village on Lake Titicaca, Bolivia. This is mostly a quick stop for people choosing the hard way (walking) between Isla del Sol and Copacabana.
By chartered boat from Yumani, walking or motorized from Copacabana. It should be possible to be rowed across to Isla del Sol, at 15 Bs pp. A motor boat costs about Bs 70 for a full group. Beware that some boatmen will try to charge you entry fees to the island. Don't pay unless you get a ticket freshly torn of a pad.
Tiny and walkable.
There is a restaurant.
And there is a hostal.
Walking the 17 km to Copacabana is quite spectacular, and you will mostly have the sun in your back going south.