Subscribe to Calendar on iPhone
Step 1 - Launch the Settings app on your iPhone or iPad.
Step 2 - Tap on Mail, Contacts, Calendars.
Step 3 - Tap on Add Account... under the Mail section.
Step 4 - Tap on Other.
Step 5 - Tap on Add Subscribed Calendar under the Other section.
Step 6 - Enter or copy in the server location of the calendar. This is typically a web address that ends in .ics.
Step 7 - Do NOT enter any username, password, or SSL. Most times you don't have to with public subscriptions.
Step 8 - Tap the Next button.
Step 9 - Tap the Save button.