I just called TP's US# and was told that their check-in counter opens 3 hours prior to flight and that online check-in is currently available. But their reps are not experienced and are not well trained, they tend to have to check with secondary support before they come back with an answer. On a different matter (my flight was cancelled and automatically rebooked to a day earlier without my input), the secondary support gave me a wrong answer. So I am not necessarily confident about their answers and am therefore asking on here for real life recent experience.