I'm thinking of flying to the Danish city of Billund next month.  I was wondering if there are any Danish posters on here with advice on how to travel from Billund airport to Copenhagen. And any tips on what to do there especially if you want to enjoy the nightlife.  

All help appreciated! 

Yes, I am danish. If you order in good time, you can get a cheap flight (by danish standards at least) from Billund to Copenhagen. Otherwise you would take the bus to Vejle and change to train to Copenhagen.
Since I've never lived in Copenhagen, I am not too familiar with the night life. But of tourist stuff I would recommend Nyhavn, Tivoli, Frederiksborg Castle and Kronborg (Though both are quite a bit from Copenhagen).
The Little Mermaid I guess is mandatory, though many get disappointed, it really is 'little'.

I'm more looking at drinking and party options in the city then tourist stuff. Is it true the nightlife in the city stays good until even 6am in the morning?  That's the time I arrived back to my hotel in Cardiff after a recent night out lol 

There are a number of flights I could take to billund but I assume no matter which one I take there won't be too long a wait to get the bus to vejle? 

And really,  you can fly from Billund to Copenhagen?  Didn't Know That. Which Airlines Do It ?

Edit : Looks Like Flights Are Too Expensive . Around €80.. How Much Am I Looking At Paying FOr  A Bus And Train To Copenhagen ? Btw Sorry For The Caps , My Phone Gone Crazy .

I don't follow lol

I hope you enjoy it. I don't have specific tips, but try to find tourist spots that AREN'T heavily visited. For instance, don't visit the Mona Lisa in France if you don't want to be massively disappointed. Also, checking out the food is usually the best part of the trip - stuff yourself until you can't eat.

My first post on the site.

I'll recommend using the site www.rejseplanen.dk for travelinformation using train and buses in and outside of Copenhagen. The site is Danish by default but can be changed. Please note that public transport isn't cheap, atleast not outside of Copenhagen. So travelling from Billund to Copenhagen can be quite expensive unless you are lucky finding cheap tickets.

I don't know much of the Nightlife in Copenhagen but i'm sure you can find several locations where there will be open to six in the morning.

That's hilarious.  Yeah I forgot they won the euros.  One Of The Biggest Upsets Ever .

Thanks.  I can fly from Dublin to billund for just €23. Or Dublin to Copenhagen for around €120. I'll have to see how much the bus to the train station and train to Copenhagen is first to decide if it's worth it. 

Would you recommend I buy the bus and train tickets on the day we arrive or get them now?  Btw welcome to the site :)

Edit: So it looks like €4-€6 for the bus and €28-€45 for the train.

So you're going to Legoland?

For Kobenhavn I would rent a car or take the train, maybe even stop at Odense (which is Hans Christian Andersen's birthplace).
Just enjoy the small city center of Copenhagen, various places you can go, but you can end the day at Moose Bar.

Can you rent a car and drop it off in Copenhagen? 

We're actually going for the world cup qualifier between Ireland and Denmark. I hear drinks are very expensive there.  but I also hear drinking on the street is allowed.  I've a feeling half of the Irish travelling will be buying cans and drinking on the street xD

So I was looking at train tickets.  €37 if you are 25 or under.  €50 if you are over 25. Are they strick on that?  My friend is 25 now but will be 26 by then.  My other friend is just gone 26. Would we get away with the cheaper tickets? 

And accommodation in Copenhagen is meant to be very expensive.  Any tips?  Preferably would like to not pay more then €100 per room per night.. 

You can always rent a car in one place and drop it somewhere else, it just costs more money.
I would have thought you had the return flight at Billund, so you could use the rental as a means to get back.
Just check how much it costs, it might be cheaper than the train if you are a group.

For accommodation maybe look around the outskirts,
somewhere that is nicely connected via the train so you can easily get to the city.

Copenhagen has a bunch of nightlife activitites. You can read about some of them here. Accomodation in Copenhagen is really expensive. The hotels are really good but if you're travelling on a tight budget I'd suggest checking out Airbnb or hostels.com. Cheapest way to travel from Billund to Copenhagen would be by bus or train. Just ask for help in the airport. People are really nice.
Bus from Billund to Vejle ~ 7€
Bus from Vejle to Copenhagen ~ 17€ (book well in advance on flixbus.dk)
Train from Vejle to Copenhagen ~ 12€ (book well in advance on dsb.dk, only "orange tickets" (tickets that are booked early) are that cheap)

I'm from Denmark. Grew up in Randboeldal (Randboel Valley) approx. 10 km from Billund. The nature is pretty great in this area (forest valleys and lakes) combined with historical Viking landmarks (Rune Stones, Viking ships, etc). If you visit places even closer to the sea in Eastern Jutland, the nature will be great as well.

I suppose you already know about attractions in Billund like:

Legoland

Lego House

Lalandia