As I didn't have any watercolour paper in large enough sheets for toddlers to work on I used large pieces of lining paper and it worked well enough.
A few of the children were a little unsure at first - it's obviously a different consistency to the ready mix paint they're used to! Some of them wanted to do their favourite thing - handprints - so stuck their hands straight in! But they soon realised that watercolour paints aren't great for handprints and got stuck in with the brushes, swishing and swilling the colour over the large sheets of paper. They seemed to really enjoy the bright colours and how easily they could move the brush and paint across the paper
Some of the older children really enjoyed trying wax resist patterns and pictures (with a bit of adult help at times). We also tore up strips of tissue paper and tried painting on them and sticking them on, gluing them on and painting over.....lots of lovely and quite summery paintings were produced!