The Pebble Time is 9.5 mm [0], and Pebble Time Steel 1mm thicker, making it 10.5mm [1]. 10.5mm is actually as thick as the current Pebble Steel so it's actually not bad.
That's pretty amazing when you consider that Apple Watch will be about 12.4mm thick with the heart sensor included and high end traditional watches can be anywhere between 11 and 13mm.
