HTC U12+ won't include a headphone adapter to let you use traditional 3.5mm jack headphones with the given USB Type-C port. Thankfully, the flagship does include USB Type-C powered HTC USonic earbuds in the box, complete with active noise cancellation. The decision to exclude the headphone adapter makes HTC a distinct player against companies such as Apple, HMD Global, and Google that all include a headphone adapter to give backward support with their models that don't have a 3.5mm headphone jack.
As confirmed by HTC USA on Twitter, the U12+ doesn't ship with a bundled 3.5mm to USB Type-C adapter. "We'd like to thank you and congratulate you in advance for your upcoming HTC U12+, Aaroni. However, it does not come with a headphone adapter. It includes HTC Rapid Charger 3.0 with USB Type-C cable, HTC Clear Case, and HTC USonic Adaptive Earphones," the company tweeted in response to a customer query around the availability of a headphone adapter with the new smartphone.
The absence of the headphone adapter from the retail box of the HTC U12+ will make it difficult for users who want to plug in their 3.5mm headphones or connect their smartphones with their in-car stereos. Of course, they can buy a USB Type-C to 3.5mm headphone jack adapter separately. But this is presumably the first time when a vendor who has opted to abandon the 3.5mm jack from its smartphone is not including a headphone adapter. Interestingly, the scenario wasn't the same with the HTC U11+ that had a USB Type-C to 3.5mm dongle in the box, as well as the USonic Adaptive Earphones.
Having said that, the bundled HTC USonic Adaptive Earphones are fine enough to fulfill your daily music cravings. The earphones do have advanced Active Noise Cancellation that is touted to monitor environmental sound levels to adjust the sound output to compensate for new noises.
It also appears that the decision to remove the headphone adapter in the HTC U12+ box may not apply in all launch markets. This means in your region, HTC might bundle the essential accessory to let you connect your old audio devices with the latest flagship.