hi mate i just got back from Vietnam myself. i spoke to a guy that used to be a fisherman. he said to get to the fishing grounds its about 5hrs+ sometimes more.. not much close to shore.

if you want to go fishing, look at going to a place called Mui Ne.. its really windy but its an old fishing village and you may be able to get on a fishing charter of sorts.. 

either way good luck and enjoy the place and people.

btw:

cam on = thank you

lam on = please

kong cam on = no thank you (you will use this lots with all the hawkers hah)

 Thanks heaps Sami are there any rivers or anything in closer ?

 Nah wouldn't bother fishing mate...everything in close has been raped

i can give you address if paid fish ponds where you catch big ass prawns with nippers and they will cook it for ya...they will also bring beer :p

can help you with other stuff but fishing is probably non existent. I go back a few times a year and my dad is from mui ne. 

P.s mui ne is full of Russians which can be fun :)

g'day I had 2 months in Vietnam and nearly married one of the locals, I bet u never leave!..
sea fishing I think you will be disappointed but if you ask enough taxi drivers there are fantastic restaurants that your can fish for large tilapia and then they fry them up for you, good fun.
I used to wake up everyday excited about eating, they really are gourmets.
wow wait till you have a Vietnamese coffee with condensed milk,-so strong you get a bit of a hot flush.

enjoy its an awesome spot. (danang rocks!)

 Thanks  jorn and Andy