iMessage

iMessage is Apple's end-to-end-encrypted messaging service, built into the Messages app on iPhone, iPad, Mac, and Apple Watch. When you send a message to another Apple user, it goes over the internet (Wi-Fi or cellular data) via Apple's servers, encrypted end-to-end so neither Apple nor your carrier can read it. Visually it shows up as a blue bubble. When you message someone without iMessage (Android user, etc.), it falls back to SMS (or RCS, since iOS 18) and shows up as a green bubble.

What iMessage gives you over SMS

• End-to-end encryption — your carrier and Apple can't read the contents.
• No per-message charge — uses internet data, not SMS billing.
• Higher quality media — full-resolution photos and videos vs SMS's 160-character limit and MMS's 320p compression.
• Read receipts and typing indicators (optional, per chat).
• Reactions, replies, group chat polls — features SMS lacks.

iMessage and your phone number

iMessage uses your Apple ID OR your phone number for delivery. When you switch carriers, you may need to toggle iMessage off and back on to refresh which phone number Apple has registered. If you switch from iPhone to a non-Apple device, you should also disable iMessage at deregister.apple.com — otherwise your number stays "trapped" in Apple's iMessage system and SMS from iPhones won't reach you for up to 45 days.

iMessage vs RCS in 2026

Apple added RCS support in iOS 18 (late 2024). RCS is the carrier-supported messaging upgrade to SMS — typing indicators, read receipts, high-res photos cross-platform between iPhone and Android. iMessage didn't go away; iPhone-to-iPhone still uses iMessage with full E2EE. The change is that iPhone-to-Android texts now use RCS instead of MMS, so they finally feel modern. The blue/green bubble distinction still exists.

Why iMessage matters for plan choice

If everyone in your group chat has an iPhone, iMessage works regardless of carrier — no per-message charges, no SMS allotment. If you're mixed-Apple/Android, RCS now handles the cross-platform case via cellular data (so it counts against your data plan, not SMS). For most users in 2026, the per-message cost of texting is effectively zero on either platform.