I believe the main problem is the hole for the barometric sensor that's located under the strap on top of the watch. Gordon has mentioned that you could basically get an IP68 equivalent seal to the watch by filling this with super glue (but you'd of course lose the use of that sensor).
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I believe the main problem is the hole for the barometric sensor that's located under the strap on top of the watch. Gordon has mentioned that you could basically get an IP68 equivalent seal to the watch by filling this with super glue (but you'd of course lose the use of that sensor).