Is iPhone 6s case same size as iPhone 8?

Looking at the dimensions of the two models, they are very similar, but the camera position is different.

Take a look at this table comparison, choosing the two models:

iPhone - Compare Models - Apple

Regards

Giulio

No.

iPhone 6s: 138.1 H x 67.1 W x 7.1 D mm

iPhone 8: 138.4 H x 67.3 W x 7.3 D mm