Hidden behind cover
In order to make the phone waterproof, all of the connectors have hinged covers. At the top left you'll find the Micro USB port for charging the phone or connecting it to a PC. It also supports MHL for connecting the phone to a monitor or compatible TV. The right side has the SIM card slot, and the top of the phone has the headphone jack. It would be interesting to find out how long these covers keep the phone waterproof, as you will frequently access the audio jack and Micro USB port, and at some point they are bound to wear out.
The only physical buttons are the power switch and volume buttons, located around the middle of the right side of the phone. Not everyone will be equally happy about the placement of the buttons. When you hold the phone in your left hand, it's easy to reach the power button. When you hold it in your right hand, it's not, and you have to move your hand before you can do so. Operating the volume buttons is even more challenging with the right hand, and it's not that easy either with the left hand. This has to do with the quality of the volume buttons, which should have been better for a product in this price segment.
On the left are the two contact points for docking the phone. These are quite deep (like on the Xperia V) and will collect dirt, so keeping these clean is something to keep in mind.
In terms of wireless connectivity the Sony Xperia Z has everything you could wish for and more. You get dual-band Wi-Fi, Bluetooth, Wi-Fi Direct and NFC. NFC is something that Sony is really championing, and not just in phones, but even in its speakers.