I just want to share what we do in my house, because despite what many parents say - not all children have phones! It is totally fine to do something different regarding phones.
This has ended up being really long!
My children don't have phones. My eldest is almost 15. As a family, they have access to a shared Nokia phone which they can use to text friends to arrange meet ups or days out. They can occasionally take the Nokia out with them if they make a reasonable argument that it would be helpful for them to have it (eg, taking a train to meet a friend whose house they haven't been to before). They walk 2 miles to school each day, and 2 miles home, usually not together. They travel to their dad's house every other weekend - which involves a train, a walk across town and then a bus.
Safety: Regarding them being out alone and with no phone on them - my teens have both had problems when out and about. It obviously does happen. One time my son needed help. He went and knocked on the door of a child in his class. The mum helped him. Another time my daughter had left her bag at an after school sports event, had to turn back for it, and was then going to be home much later than she knew we were expecting her. She called into a shop and asked to use their phone to let us know. Problem solving and resilience building!
Socialising: If someone wants to meet up with them, they can send a text to the Nokia or phone our house. I know kids use WhatsApp, SnapChat etc, and that texts and phone calls are not the normal thing these days. But I taught my kids that if their friends care, a little inconvenience of having to make a phone call, or send an old school text isn't going to stop them. And it hasn't! My kids have great social lives. And they actually seem to have a lot more freedom and independence than many of their friends.
School: There is a definite assumption by the school that everyone has a smartphone in their pocket at all times. In some computing lessons, they have both been asked to take out their phone to access an app. And you know what - each and every time - they are not the only child in the class with no phone! And they either work with a friend for the lesson, or they use school devices. Re homework - it is set online, but we can access the site (most families seem to access it as an app, but the website works just as well). So they can use a laptop at home to access their homework and their school emails, etc.
How do they feel: They accept it to be honest! They know this is a non-negotiable hard no.
So honestly, it just isn't true that all teens have phones. Your child will be fine without!