Cardiff is a very lovely city almost 3 hours away from London by car. You can also travel by train or even airway. However, driving to Cardiff would be a better option from London. That way you can stay in a budget hotel outside of Cardiff by 20 minutes drive or so. It will be not only cheaper but also more flexible to handle accomedation.
We suggest Ibis Budget at NewPort as one of the best affordable options available out there. It is really cheap and provides basic breakfast. Due to its location being just next to main highway connecting to Cardiff, it is really convenient to stay there. It takes ~15 minutes driving to Cardiff city center.
Day 1: City Center & Main Attractions
Cardiff is a very established and also historical city. When you park your car on a public park space, available in a lot of places, the city centre can be easily seen by walking. Most of the attractions are nearby 5-10 minutes distances.
Dating back to a very old times, it has a nice coffee shop you can buy muffins and coffee or tea. The restrooms are well maintained and support childcare facilities. The vast open grass garden and tunnels, stairs around the walls are really enjoyable. Especially with your kids, you can just leave them free and let them explore, climb, run and sunbath (if you are lucky) in this historical heritage.
Wales Millennium Centre & City Port
Being a city nearby see side makes Cardiff City Port a place to joy. When the weather is sunny, it could remind you the likes of Stockholm port. Clearly, it is one of the places locals are also spending time.
There is some vegetarian ice-cream options available to enjoy the viewing. The Millennium Center has some other facilities for childcare but doesn’t provide great food options.
Day 2: Brecon Beacons National Park
This is by far one of the best national parks preserved in the United Kingdom. It is just wonderful. You can drive there from Newport or Cardiff City Center around an hour. The road itself is also beautiful. The rest of the details cannot be easily explained so let’s enjoy some iPhonagraphy we took there: