iPhone 17is heating on mobile service

An iPhone on 1 bar can use up to 10x as much energy as 5 bars or Wi-Fi. That energy is converted into heat and thus heats the iPhone up and drains the battery as your iPhone has to work much harder to reach the cell towers. How is your connection on a day to day basis? Have you been in any remote places recently? Try to be using Wi-Fi as much as possible when at home and other buildings. And if this is always the case with your connection, try reaching out to your carrier.

Thank you for the clarification. Because this is a new iPhone, it is expected for it to have an increased battery drain and thermal temperatures upon setup for the first few days as a result of setup processes, not the cellular. This is because your iPhone has to extra hard to index all of your data and more. Indexing is when your iPhone sorts your data and files for search, also why you may notice some search functions don't work as well initially but later populate. Your iPhone also is updating apps, downloading new assets etc. New features also require additional resources, such as Apple Intelligence.

Be sure to charge your iPhone all night, every night, to allow your iPhone to best index. Your iPhone does most of its indexing on the charger, and on a strong connection.

hristo260 wrote:

iphone 17 is heating when on mobile service and the battery is draining fast. How to fix it

Restart your phone.

Do a force restart Force restart iPhone - Apple Support

If your cellular data connection is week, it will make your phone hot and drain battery as it searches for a stronger signal.

Report the issue to your cellular data provider or look at their help forum.

hristo260 wrote:

Thanks for the feedback. I am in a city with excellent coverage. Speedtest today indicates 1000 mbps.

It has nothing to do with what the coverage is in the city as a whole. I had to do with what kind of signal you are getting where you're standing. I live in a major city that has great coverage. However, for a variety of reasons, the first floor of my house has a poor signal. That can affect my battery no matter how good the signal is upstairs.