Is there a difference regarding battery between Apple Watch 38 mm and 42 mm?
Apple used to say that the larger Apple Watch ‘typically experiences longer battery life’ on their Apple Watch battery information page, however they removed this line from the page when the Apple Watch Series 2 was released.

The mAh specifications are as follows:


Apple Watch (original) &amp; Apple Watch Series 1, 38mm: 205 mAh (source)
Apple Watch (original) &amp; Apple Watch Series 1, 42mm: 246 mAh (source)
Apple Watch Series 2, 38mm: 273 mAh (source)
Apple Watch Series 2, 42mm: 334 mAh (source)