Rent a car in North and South island of New Zealand

We will be going to New Zealand in a few months. I did a lot of research for car rental. I've decided Apex is the most reasonable and easiest to work with. If you want to pick up a car in Auckland and drive to south island and come back, they are your best bet. Their cars can go on the ferries and they purchase the ferry tickets for you.

That said, if I could do over, I would check a one way rental Queenstown to Auckland for price. Apparently, if you want to do a one way rental, that is the most economical way to do it. I was deep into my planning and had already reserved a few places before I found that out.

As you plan, you will find out three weeks is not enough time. You will have to make some brutal choices. Some might recommend that you pick just one of the islands.

If you haven't found the New Zealand Travel Tips facebook page, you really should. Tons of information and they do some nice discounts. It is worth signing up for Facebook just to access the travel tips. You can also ask questions there and you will get lots of responses.

Lastly, use the search bar on this forum to look for recent posts. You will find some, I know, because some of them were mine.

We've spent quite a lot of time in NZ, including a couple of post retirement trips of 90 days apiece.
My suggestion would be to relax for a few days in Auckland upon arrival - shedding some of your jet lag, generally enjoying the city, and taking advantage of local tour companies for day trips around the North Island. Then head down to the South Island for the majority of your time in the country.
There are cheap and frequent flights from AKL to a variety of destinations on the South Island. A one-way rental between Queenstown and Christchurch would be optimal I think, but the one-way drop charge might preclude that, so renting your car at one or the other and doing a circuit might be the cheaper option.
Personal opinion only, but given your limited time I wouldn't devote most of a full day to the crossing on the Interislander ferry between Wellington and Picton. Besides, the one-way drop charge for a rental car is likely to be quite expensive.
Also, I wouldn't agonize too much about trying to craft the "perfect" itinerary. The whole country is gorgeous and you can't go wrong no matter how you organize things, though I would make the point that most of the spectacular "Lord of the Rings" scenery (and film locations) are on the South Island - and in the vicinity of Queenstown and Te Anau in particular.

Just to clarify, with Apex, the one way from Queenstown to Auckland can be, and typically is quite reasonable. So if that is something that may be of interest, check it out. The one way from Auckland to Queenstown, definitely is cost prohibitive. I think so many people fly into Auckland which might explain why this tends to be the case.

I would agree with what Robert said about the ferry, it’s a very long trip, and you only have three weeks, don’t waste so much time on a boat. Also, though the country looks small, it takes more time to get around than you might think. Personally, I spent my whole three weeks on the north island going all the way up to 90 mile beach, and down as far as the Rotorua area. Friends of mine who just returned spent all three weeks on the north island, also. A cousin of mine spent an entire year on the South Island. I think with just three weeks it might be a good idea to decide which interests you the most and spend the entire three weeks there. The Lord of the Rings scenery is definitely on the South Island, but Hobbiton is on the north island. There is an amazing Kauri forest on the north island, but the south has Milford sound. I saw lot of mineral pools, a geyser, and the glow worm caves on the north island, but that’s what interested me. Do more research before setting your mind on where to go.

I think Tom was the first person to tell me about the one way from Queenstown to Auckland, and I've been hearing the same from others, so I don't think it's just a random occurrence. People do seem to really like Apex. Originally, I was working with Autoeurope, I've had reasonably good experiences with them in Europe, but in the end, Apex seemed to have a better handle on the ferry, and their pricing was good. (As long as you don't want to do a oneway Auckland to Queenstown.

I spent months obsessing over an itinerary and trying to figure out how I wanted to manage car rental. There are pros and cons for each possible itinerary/car rental scenario. If you fly to Queenstown, you might end up buying the ticket last minute or spending an unwanted night in Auckland. I constructed loops on each island, and I do like the itinerary I finally landed on, but as I continue to research/plan, I hear other itineraries that make a lot of sense.

I was intrigued enough about the Apex discussion that I decided to take a look for myself.
The one-way rental from Queenstown to Auckland does indeed look like a winner. Their quote for a 3 week rental next November is extremely reasonable and the cancellation policy is pretty liberal should plans change. Including passage on the Interislander is a nice bonus, and they have generally good reviews on TA.
Fact is that I've bookmarked the Apex website for one of our own future trips. There's a lot to like here.

It depends on what you want to do. Create a map with the sights you want to see. This will help you figure out your route and what you should do. We rented a car on the North Island, made a small loop, returned the car, flew to the South Island, rented a car there, and made a larger loop. It made sense for us given what we wanted to see and do. We rented cars from Apex to save money, and used https://www.grabaseat.co.nz/ to get a good deal on our flight from the NI to the SI.

I agree with Lane on mapping out the cities that you are interested in. However, I would do a very rough itinerary and then look at the implications in terms of rental cars. I had a couple itineraries in mind but when I checked for car rental, the pricing was crazy so I went back and constructed a new itinerary.