A plausible report says that the iPhone 15 Pro will retain the iPhone 14 Pro maximum 27W charging power, despite rumors of it rising to 35W with Apple's change to USB-C.
USB-C charging port on the iPhone 15 Pro (Source: Apple)
Those previous rumors about 35W were backed up by how Apple launched a 35W dual charger in 2022. Then, too, one of the expected benefits of switching to USB-C was a faster charging rate.
Now, however, Japanese blog Mac Otakara, it hasn't happened. Instead, both the iPhone 15 and iPhone 15 Pro models are said to support a maximum of 27W for charging.
Mac Otakara does not cite its sources, so until the iPhone 15 range can be tested it's possible that the report is wrong. However, Mac Otakara has a good reputation for its information. With first reviews of the new iPhone expected on September 19, it's likely that the blog is correct.
The move to USB-C, ultimately because of the EU's mandate, seems to bring no benefit over Lightning for iPhone 15 and iPhone 15 Plus users. For the iPhone 15 Pro models, it does offer faster data transfer rates, which for one thing enables filmmakers to shoot video directly to external drives.
It's also potentially convenient to have the iPhone on USB-C when so many other devices, including several Apple ones, are. But USB-C is also a confusing standard, and people will need adapters or new cables.