Hi there! We've been doing the long weekend thing for 4 years now - its really good!! Sometimes we have stayed at the Don Quojite Figuertas - really really cheap, bit tacky - predominantly gay/spanish hotel - but a fantastic roof top pool (views anyway) and inbetween space and ibiza town. This year we stayed at Tivoli apartments pdb but didn't get to stay there - they hoofed us off down the road to their sister hotel - so I dont recommend this one - although it was nearer space

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We always take hand luggage only and if you are arriving at what you think may be a peak time - then book a transfer in advance (we usually arrive at night ) as there is a bloke waiting there with your name on and its hilarious when you go outside and see the mile long taxi queue when you are gagging to get clubbing! I've not done without a hotel yet - but most of the hotels/hostels in pdb are ok and lets face it you are hardly ever in the room - this year the 5 of us went and we landed friday night - went out, went out saturday morning, then slept at about 8 oclock in the night for 2 hours, then went ibiza town drinking (vodka helped with the sleep deprivation by then!) then went out saturday night - had a couple of hours sleep sunday morning then we realised we were hungry - ate something crap and then danced at bora bora all day till midnight when we had to go airport to get home. so really apart from 4 hours at the hotel we weren't there. . . it was only 140 quid between the 5 of us for the room though. have loads of fun - and my best tip is WEAR ALL YOUR HEAVY STUFF and decide on your outfits (female tip) before you go so you only take what you really need - a change of shoes/flipflops/trainers are good if you are dancing loads the last thing you need are uncomfortable feet!
Hope this helps and sorry about the long post - but I love my weekend trips!