How to Subscribe and Sync Apple Calendar with URL in 2025: Complete Guide

Apple Calendar subscriptions update based on your auto-refresh settings. You can set them to refresh every 5 minutes, 15 minutes, hourly, daily, or weekly. The default is usually every hour. For real-time updates, choose a shorter interval, but be mindful of battery and data usage.

No, subscribed calendars are read-only. You cannot edit, add, or delete events in a subscribed calendar. To make changes, you need to modify the source calendar that generates the subscription URL. This limitation ensures data integrity and prevents conflicts between multiple subscribers.

Subscribing creates a live connection that automatically updates when the source calendar changes, while importing creates a one-time copy that won't update automatically. Subscriptions are better for dynamic calendars that change frequently, while imports are suitable for one-time calendar transfers.

Apple Calendar supports iCal (.ics), CalDAV, and Exchange calendar formats. Most calendar subscription URLs use the iCal format, which is widely compatible across different calendar applications. The app also supports vCalendar (.vcf) files for individual event imports.

This usually occurs due to iOS restrictions on HTTP URLs or network-specific issues. Ensure you're using HTTPS URLs, check your Wi-Fi/cellular connection, and verify that the subscription is associated with your iCloud account. Sometimes removing and re-adding the subscription on iPhone resolves the issue.

Apple doesn't specify a hard limit for calendar subscriptions, but performance may degrade with too many active subscriptions. We recommend keeping under 10-15 active subscriptions for optimal performance. You can always hide calendars you don't need regularly without unsubscribing.

Yes, Apple Calendar caches subscribed calendar data locally, so you can view events offline. However, the calendar won't update with new changes until you have an internet connection. The amount of cached data depends on your device's storage and the calendar's refresh settings.

You can share the subscription URL with family members so they can add the same calendar to their devices. However, subscribed calendars cannot be shared through iCloud Family Sharing. Each person needs to add the subscription individually using the same URL.

If the source calendar becomes unavailable, your Apple Calendar subscription will stop updating but existing events remain visible. You'll need to update the subscription URL if the calendar moved, or remove the subscription if the calendar is permanently deleted. Apple Calendar will show sync errors for unavailable subscriptions.