Lisbon to Porto, train or flight?

Hello guys! I've booked a flight to Lisbon in August for 6 days intending to spend all the days at the capital. Searching though, I found out that Porto is beautiful too so I'm thinking of spending a day there... I've searched for flights with TAP and tickets are really cheap. I guess though it's better to book a hotel in Lisbon for all five nights and escape to Porto for one day. Is it possible to do it with a train leaving morning from Lisbon and then returning back late afternoon? How many hours is the journey and can you suggest me a website (I hope it's in English!) to book my ticket? Any ideas of the ticket cost (anyway i will figure out in the site):-)
If I have to book the flight then I will then have to spend at least an evening in Porto since it's gonna be a huge hassle flying there and back within one day!
Any help/suggestion is appreciated.
Thanks in advance guys!

It's 200 miles/300 kms from Lisbon to Porto. By train it takes about 2 hrs 30 mins hours from city centre to city centre. I'm sure you can work out how much time that would take to get from A to B and back again if you take a flight, and how your carbon footprint would compare if you take the train.

I'll lay you a bet. If you and a friend leave you hotel at the same time, one of you will still be at Lisbon airport when the other's train gets into Porto.

Skybluem, were our replies of any use to you? Since we invested some of our free time in giving you advice, it would be nice to hear from you.

You should spend more time in Porto. At least overnight stay...You will be impressed with the city and it is so different from Lisbon

Hello Guys, thanks for the advice I got from you! I would get back to you anyway! Aribo, indeed, it seems that I will be getting the train. I dropped the idea of the flight since for sure you spend much more time for the whole procedure (including the check-in time). Thanks for the Portuguese railways site! I checked it already. It was helpful you gave me the exact train stations I need to insert in order to search for the route.

I know Porto is a beautiful city. This is what I get from the photos and it would be great to spend a night there. But, what I'm thinking is the whole thing carrying luggage etc for spending an evening and then coming back. I like adventure but all this for 1 night?
For the time being I'm seeing the Lisbon-Porto as an 1 day excursion, leaving in the morning and coming back in the evening.
I love travelling with train. I'm sure the route is a beautiful one!

Thanks guys one again!

I am planing on visiting Portugal for about 10-12 days this summer and Id like to see Lisboa and Porto, so how many days do you guys suggest on spending in Porto and how many days in Lisboa? Id also like to visit Lisboaa`s beaches and I was wondering if they are accessible with public transport ?

Regards