I was recently commissioned to do some outdoor cement circles for a butterfly garden. I am assuming cement/concrete primer to start, but can I just use regular acrylics for the actual painting and a good urethane sealer? Not sure if I have to use an outdoor enamel...

Thanks,
Julie

I would suggest exterior enamel.

If you are after transparent look of the paint, then put the pigment directly into the sealer.

If you are looking for the UV protective sealer - do not waste your time, use non-fugitive paints - aka paints made of natural pigments.