This is how I modified the soaker pattern for circular needles. I did this because my least favourite part of knitting is making up and sewing seams. So if I can find a way of changing the pattern to reduce the amount of making up, I will! With this pattern now, the only seam I sew is the waistband, and the sides and crotch are seamless!
Using straight needles, I provisionally cast on (see http://www.knittinghelp.com/video/play/invisible-provisional-cast-on), then knit to row 10. On row 11, use your circular needles (40cm I think) to cast on the next 2(3:4) stitches and finish that row. All stitches will now be on your circular needle.
Now thread the 19 stitches from your cast on edge onto your straight needle and start from row 1 again, working through to row 10. You will have the circular needle holding your other live stitches the whole time as you knit back up from the cast on edge.
On row 11, place a marker then use the circular needles to cast on the next 2(3:4) stitches and finish that row. Place a marker indicating the end of the round. You should have a marker at each side of the pants now.
You will now have all of your stitches on the circular needle, with the crotch of the soakers (your now invisible cast on edge) hanging in a loop underneath. Continue with the pattern, skipping the purl rows because as you are now using circular needles, you will only be knitting from the right side of the fabric. Also note that you are now knitting both sides at once, so you will need to make sure you follow the pattern, in effect knitting each row twice.
It will be a little tight until you knit a few rows up from the crotch, because the loop will restrain the movement of the needles somewhat. Once you get a few rows up, it should loosen and you will be able to knit more comfortably.
When you get to the ridge row, you will just need to purl a round.
Enjoy!










