A configured Echo can use its internet connection to place an Alexa call while your phone is elsewhere. The speaker supplies the microphone and audio output. Which destinations it can reach depends on the calling service available to your account and region. Calling another Alexa user and dialling an ordinary telephone number are different cases.
Set up before putting the phone away
Open the Alexa app and check Communication. Complete any required phone-number verification and confirm the contact you want. Setup may still require a phone even though a configured Echo can make a call without one nearby. Bluetooth pairing by itself does not activate the Alexa calling service.
Choose the destination deliberately
Ask to call a known contact and make clear whether you want their Alexa devices or a particular phone number. If two contacts share a first name, use their full names. When a regular number fails but an Alexa contact works, check regional support and the type of number before changing the speaker or router.
Keep a separate emergency route
Amazon lists emergency numbers among destinations unsupported by ordinary Alexa Calling. Keep access to a phone or another suitable local emergency service. An Echo also depends on power and network access. An ordinary incoming call allows the recipient to answer; an authorised Drop In uses a different connection model.
For the documented details, see Alexa calling limits.
Common questions
Does my Echo need a SIM?
An ordinary Wi-Fi Echo uses an internet connection.
Does pairing my phone enable calling?
Pairing audio and setting up Communication are separate.
Can I call any number abroad?
Check supported destinations for your own account and region.
Can I use it during a power cut?
Do not depend on the Echo or router remaining powered.