Lossless will play back normally on Bluetooth speakers and headphones. However, Bluetooth connections don't support lossless audio.
Can you listen to Hi-Res over Bluetooth?
Hi-Res audio cannot be streamed using Bluetooth speakers, because Bluetooth technology does not meet the Hi-Res specifications due to bandwidth limitations. However, devices such as the Sony NWZ-ZX2 Walkman with the LDAC technology offer an enhanced wireless listening experience for all your music.
Can you play FLAC over Bluetooth?
FLAC files can also be streamed via Bluetooth with the aptX codec. AptX is a lossless compression method for Bluetooth that supports CD-like quality. That means, you'll hear the full bandwidth of a 16-bit/44.1 kHz recording.