Can coffee and tea count toward hydration?
Yes. Coffee and tea contribute fluid. Caffeine can have a mild diuretic effect, especially in people who are not habituated, but the water in the drink usually more than offsets that in ordinary servings. In practical terms, unsweetened coffee and tea count toward hydration for most people.
They may also offer benefits beyond hydration. Coffee and tea contain bioactive compounds such as polyphenols, and observational research often links regular coffee or tea intake with favorable health associations. That does not make them magic, and it does not mean more is always better, but it is a reason not to treat them as merely "not water". They can be enjoyable, low-calorie, routine-supporting beverages that fit well in an overall healthy diet.
The bigger issue is timing, dose, and what gets added. Coffee late in the day may hurt sleep even if it helps alertness, and poor sleep can make hunger, training, recovery, and adherence more difficult. Sugar, cream, syrups, and large specialty drinks can also turn coffee from a low-calorie beverage into a meaningful calorie source.
Decaf coffee and decaffeinated or caffeine-free tea can still contribute to hydration and enjoyment, and they may preserve some of the same non-caffeine compounds. If you like the ritual, but caffeine affects anxiety, reflux, sleep, or heart rate, decaf or caffeine-free can be a useful substitution. If your caffeine use is steady and sleep is good, coffee and tea can stay. If sleep is worse, move caffeine earlier before cutting fluids.