Andhra Pradesh is spread out, so trying to 'see it' in a day is a trap. I'd anchor your first day in Visakhapatnam — Vizag — which packs coast, hills, and a bit of quirk into one easy loop.
1. RK Beach & 2. the submarine
Start along RK Beach on the Bay of Bengal, then tour INS Kurusura — a real decommissioned submarine turned museum, sitting right there on the sand. Walking through those tight compartments is the kind of thing I'd have loved as a kid (and honestly still do).
3. Kailasagiri & 4. Rushikonda
Take the ropeway up Kailasagiri hill for the big coastline views, then cool off at Rushikonda Beach, the nicer stretch for an actual swim. Go easy on the timing — the midday sun here is no joke.
5. Simhachalam + a caveat
If you've got temple interest, Simhachalam on the outskirts is worth the trip up the hill. One honest note: Araku Valley is gorgeous but it's a full-day journey each way, so don't try to cram it into Day 1 — save it for Day 2. If any of this has changed, you know the drill: comment and I'll fix it.
