Is it safe to drink the tap water?

No. Stick to bottled water, which is widely available at every 7-Eleven.

Yes. While malls take cards, street stalls and small boats are cash-only. Keep small denominations (20s, 50s, 100s) on you.

Navigating Bangkok as a Couple on Your First Visit

Stick to the BTS Skytrain and MRT subway to avoid gridlock, and use the Grab or Bolt apps instead of hailing street taxis. Balance your time between the air-conditioned malls and the outdoor markets to keep your energy high and tempers low.

Master the transport apps. Download Grab and Bolt immediately. Both apps allow you to see the price upfront and track your driver, eliminating the need to haggle with taxi drivers who refuse to turn on the meter.
Use the river for sightseeing. Avoid road traffic to reach temples like Wat Arun by using the Chao Phraya Express Boat. The orange flag boats cost 16 THB per person and move much faster than any vehicle during rush hour.
Plan your 'Cool-Down' windows. Bangkok is humid. Schedule your day to be outdoors between 8:00 AM and 11:00 AM, then retreat to a mall or a cafe from 1:00 PM to 4:00 PM to avoid the peak heat index.
Get a local SIM card. Buy a tourist SIM at the airport (AIS or DTAC counters). You will need consistent navigation apps to find hidden alleyway cafes and track your public transport routes.

Is it safe to drink the tap water?: No. Stick to bottled water, which is widely available at every 7-Eleven.
Do I need cash?: Yes. While malls take cards, street stalls and small boats are cash-only. Keep small denominations (20s, 50s, 100s) on you.