Changing Colours in Crochet

Working in Colour

When you are joining in, or changing from one yarn to another for reasons of colour (treble shown here), you drop the old colour and pick up the new one before you complete the last stitch in the old colour (see 1st below) so that the loop on the hook afterwards is already in the new colour (see 2nd and 3rd below).

Joining colour in crochet
Working in colour
Working in colour in crochet

When you are working whole rows in different colours, make the change during the last stitch in the row, so the new colour for the next row is ready to work the turning chain.