On every other Hawaiian island the answer is a straightforward yes. Oʻahu is the exception, and saying so out loud is worth more to you than another page telling you to rent for seven days.
Honolulu is a real city with real public transport, Waikīkī is dense and walkable, and hotel parking is priced like a city. A week-long rental sitting in a garage at $50 a night is the single most common way visitors waste money here.
What TheBus actually reaches
TheBus is one of the better transit systems in any American city this size, and for a visitor it covers more than people expect: Pearl Harbor, Ala Moana, Chinatown, Diamond Head, Hanauma Bay and, given enough of the day, the North Shore.
Fares work on the HOLO card, which caps your spending daily and monthly, so a heavy bus day costs the same as a moderate one. The Skyline rail is opening in segments from the west side and is worth checking against your plans, though it does not yet serve Waikīkī.
The honest limitation is time. Waikīkī to Haleʻiwa on the bus is a good two hours each way. That is a fine way to spend a day if the ride is part of it, and a poor way if you wanted the North Shore itself.
The two days a car earns its keep
The circle island loop. Waikīkī out to Hanauma Bay, Makapuʻu, Kailua and Lanikai, up the windward coast, over to the North Shore and back through the middle. It is a long, wonderful day and it does not work on a bus schedule.
A second flexible day for whatever the first one left out, usually the North Shore properly or a hike that starts early.
Two days of rental plus bus and rideshare the rest of the week costs meaningfully less than seven days of rental plus seven nights of parking, and you spend none of it looking for a space in Waikīkī.
The parking math
Waikīkī hotel self-parking runs roughly $35 to $60 a night and valet climbs from there. Over six nights that is $210 to $360 before you have driven anywhere.
Street parking in Waikīkī is scarce, metered and enforced properly. Beach parks fill early, especially on weekends when residents are using them, and a few of the popular ones now cap entry or charge non-residents. Reservation rules for state parks are on the Hawaii State Parks site, which is the version that stays current.
How to book it that way
Rent from a Waikīkī location on the morning you want it rather than at the airport on arrival. You avoid the airport concession fee, you avoid parking it overnight and you avoid driving the H-1 with your luggage on day one.
Get from the airport with a rideshare or the airport shuttle. It is about $35 to $45 to Waikīkī, once, which is less than one night of parking.
Check two-day rates, no prepayment
When to rent for the whole week anyway
Staying outside Waikīkī, in Ko Olina, Kailua, Haleʻiwa or Turtle Bay, flips the answer back to yes. So does traveling with small children, with beach gear, or with anyone for whom a two-hour bus ride is not a pleasant afternoon. Parking outside Waikīkī is usually free or cheap, which removes most of the argument against it.
That trade is worth doing the math on before you book the room rather than after. A condo in Kailua or Ko Olina with free parking and a kitchen can come out ahead of a Waikīkī hotel once you add $50 a night of parking to the rate, and it changes the shape of the week rather than just the price.
