It is not difficult to synchronize your TeamUp calendar with your iPhone. Generally, for iPhone users, in most cases, tapping the Teamup iCalendar feed URL will launch the calendar application, and the feed subscription dialog will appear.  If that is not the case for you, follow these steps:

  1. On the Home screen, tap Settings.
  2. Tap Accounts & Passwords.
  3. Choose Add Account.
  4. Tap Other at the bottom of the screen.
  5. Tap Add Subscribed Calendar.
  6. Enter or paste the iCalendar feed URL from your Teamup Calendar in the field Server.
  7. Tap Next. To enable reminders, turn on Events Alerts (make the button green so that you can set reminders).

After you have done the above, your subscribed Teamup Calendar will appear on your device’s default calendar app using iCal. You can then set the calendar’s color or turn the Event Alerts button on or off.

If you subscribe to a Teamup iCalendar feed containing multiple sub-calendars, the colors for each sub-calendar on your original Teamup Calendar will be lost.  Instead, you can assign one color from your iPhone/iPad for the entire Teamup Calendar feed.

To change the update frequency: In step 3 above, tap “Fetch New Data” instead of Add Account. Scroll to the bottom and select the fetch frequency.

To remove a subscribed calendar from your iPad or iPhone, check out this article.

(For more details check this URL: Outbound iCalendar Feeds: View Teamup in Other Calendars)