I am often inspired by function and design out of necessity, and I am super hard on slipper socks, but I love to wear them! So I decided to make the uppers of these slipper socks separately from the soles so that the soles can easily be replaced. 

The uppers are knit first in the round for the ankle, then increases are added for the front. The side and back stitches are bound off, and the front is worked flat decreasing for the toe before binding off the final stitches. The sole is worked flat in simple garter stitch with a little shaping. The upper and sole are then seamed together with single crochet in contrasting color.  

You could make the soles a different color from the upper and seam, especially if you’re making several pairs! Any Worsted weight yarn will do, so if you want to spurge on a luxury fiber for the uppers and a utility yarn for the soles, that would totally work! You could also hold 2 yarns together for the soles to make them thicker.

Yarn (This is what I used. You can use whatever yarn you’d like.)
Malabrigo Rios - pure Merino Superwash
Worsted Weight 210 yds, 100g
Sample - Size SF (after blocking)
C1: 035 Frank Ochre (yellow) - used 64g
C2: 033 Cereza (red) - used 7g

Istex Lettlope 109 yds, 50g
Sample - Size SF (after blocking)
C1: 1404 Glacier Blue Heather
C2: 9431 Brick Heather

Needle
US6/4mm DPN or circular for magic loop
3.5mm crochet hook

Gauge
18 sts x 40 rows = 4” - Garter Stitch (sole)
17 sts x 30 rows = 4” = Stockinette (upper)

Tools
5 Stitch markers
(optional: 4 same, 1 different for BOR)
Tapestry needle

Stitch Patterns
Stockinette
Garter

The sizes fit roughly as follows, but are very easy to
modify to your individual foot.
SF = Standard Fit (see ways to make it your own)
10” circ at ankle, approx 4 1/2” x 9 3/4” overall
(L) = Larger than most (see ways to make it your own)
10.5” circ at ankle, approx 4 3/4” x 11” overall

Links to video tutorials included.