There are regular scheduled ferry crossings from Landskrona (Sweden) to Bäckviken on Ven by Ventrafiken's ferry "Stjerneborg".
The crossing takes about half an hour and the adult fare is SEK 80 return.
Well...it's an island. There are a couple of guest harbours but if you don't have your own boat, you have to rely on the little ferries that run all year round at decent frequency. Some are big enough to take a few cars and supply lorries but only the locals and permanent summer guests bring their own cars since they need to bring building material etc. Most tourists leave their vehicles behind since Ven is a small island and has plenty of other means of transportation. Cars are just in the way here. The ferries leave from Landskrona on the Swedish mainland all year round (30 minute crossing) and in summer, you can also get here by ferry from Copenhagen or from Råå just outside Helsingborg. You end up in Bäckviken village and harbour which has a kiosk and the island's youth hostel. From there, it is easy to get further on to explore Ven.
As for tickets, you can buy return ones both for the day and for a weekend. These are open tickets so you can return whenever you like which means that you have to queue in the "obokade" line along with others with open tickets rather than in the line with those who have booked. This means you'll be let on board after the booked people which could possibly present a problem in July-August if you rely on the last boat. Then better book - we never had a problem in May.
OK, if you're not fit for a bike ride, nor happy about the bus, there are more options. Groups and others can be picked up by tractor as in the picture. Otherwise, Ivan's Wagon Trail is a company with ardenner horses who take tourists around the island in one of his carriages in high season and when not, you can also book horse trekking all over the island with him if you have some riding experience. Some evenings in summer, Ivan also arranges ghost tours by horse and carriage at night :)
OK, despite the island being very small and easy to manage even for unfit cyclists, there might be those of you who cannot bike. Fear not, Venbussen is a small bus service that takes you to the major points of interest such as Kyrkbacken, the Tycho Brahe Museum and to and from the ferry. In fact, it is a request type of bus so you don't really need to keep track of the proper stops. Just signal to the driver that you'd like to get on. The bus also often waits at Bäckviken for the major ferry arrivals in high season. Not that you couldn't also afford a taxi - the island is so small that the taxi driver has fixed prices which at our time of visit was SEK 20 a person :)))
I have never seen anything like it in the cycling world! Ven is all about yellow bikes and there are hundreds of them. You rent them in a kiosk above Bäckviken harbour and off you go. Because they are all painted yellow, they are easy to spot and hard to steal :) The island is not that challenging so all bikes are without gears but there are all types of bikes, from standard singles to tandems and child bikes and with trailers and child "half cycles". You can rent them for anything from a day to a week for a reasonable sum (click on "Prislista" on the website below for updated amount) and everywhere you go on the island, you will see loads of bike parking racks full of yellow bikes :))) You can also rent extra baskets and things for the bike and if anything goes wrong, there are two other places to change bike at, namely just before the Kyrkviken village and at the camping in Husvik.
This is very nice! Small paths goes around the Island, You can ride almost everywhere and the views are breathtaking