To add calendar to IOS open your phones setting and under the password & accounts “add account” ,click “other” and “add subscribed Calendar.

Copy and paste this. https://calendar.google.com/calendar/ical/salkeiz.k12.or.us_4i5rfc4dehgqfggm1arvd8f7ms%40group.calendar.google.com/public/basic.ics

Or open your Iphones camera and scan this QR which will ask you if you want to subscribe to the swimming calendar.