These mittens are worked flat, but the thumb is knit in the round.
So you will need dpns or circular needles to knit the thumbs.
There are optional cables on the cuff, so if you choose to knit the cables, you will need a cable needle.
You will need 2 stitch markers, a tapestry needle, and waste yarn.
Seen here: Lanett merino superwash wool; 182m/50g; 3021 (light tan), 1001 (white), 1088 (charcoal), 2001 (lemon yellow), and Knit Picks Stroll 75% superwash merino wool, 25% nylon; 231 yds/50g; in Scarlet (red) and Merlot Heather (brown). 1.25 balls of light tan; ¼ ball each of brown and red; one or two yards/meters of white, charcoal, and yellow.
Remember to always bring the new color under the old color when working intarsia. I found that a backward loop cast on worked well in place of a regular M1 increase. Knitters using a black-and-white printer may wish to mark their pages while referring to the computer screen as some colors may not show up clearly when printed. (If you have never used the following embroidery stitches: duplicate stitch, chain stitch or back stitch, you may want to practice.)