Yes, you can connect the FiiO FH3 headphones to your iPhone, but there are a few things to keep in mind:

- The FiiO FH3 headphones have a 3.5mm headphone plug. If your iPhone no longer has a 3.5 mm headphone jack (like the newer models), you will need an adapter.
- You can use the Lightning to 3.5 mm headphone jack adapter from Apple to connect the headphones to your iPhone. This adapter connects the 3.5 mm headphone plug to the Lightning connector on your iPhone.

With this adapter, you can use the wired FiiO FH3 headphones with your iPhone without any problems.