New to Placencia. Nearest office for visa extension?

Hello.
My wife and I are from Nevada City California and will be living temporarily(for now) in Placencia. I arrived three days ago and she will be following in November. I have the house rented until next May. This is our original expat experience, we've never stayed out of the US more than a month at a time(except for briefly in the military).

Can anyone tell me the closest office to get my visa extended next month?

Question 2, is there an expat woodworking group in the country? I'm an artisan woodworker and I'll miss my shop. I'm also a lifelong fly fisherman so I'll find something to do!

I also think I recognize someone, Mango Man, if you're who I think, Carol and I stayed with you and Miss T last February. If so, send me a PM and I'll do my best to figure out how that works. We'd love to come up and see you guys sometime.

I hear that it is closer to take the water taxi to Big Creek, other than that it would be Dangriga

It is fast taking the Hokey Pokey I think we set a record in Feb. caught 7:50 which left at 7:40 am water taxi, cabs there waiting went got passports stamped, got back to watertaxi just in time to catch it back . We were back in Placencia at 8:30 am. Not the norm though. Also went to Dangriga in March. Both were good no one there so relitivly fast . We needed to go to Dangriga anyway so went and got stamped early. We were lucky and she stamped from our due date not the early date . But for sure Dangriga is a lot farther then Big Creek / Independence

we do the Hokey Pokey from Placencia to Mango Creek.  Taxi straight to office, very easy and fast, we have not had a problem at all.  Can easily turn around and usually catch the next water taxi back.

Thanks everybody. I went last week. Hokey pokey to Independence/Mango, then a taxi to Big Creek. It was very fast and cheap. The hokey pokey charges $6 each way, the taxi was a minivan and several of us rode for $10 round trip each. Immigration took about twenty minutes, that was for about six of us that came on the same taxi, Immigration cost $50. These are all Belize $.
So, I left at 10:00AM, was back in Placencia at 11:15AM and total cost was $72BZ. I didn't have to show proof of income, only my passport and address. Easy peasy and much more pleasant than I anticipated!

Do you need a visa or passport?  Or do you need both?

You have to bring in your passport and your money. They are or were in Feb, March 2017 putting a sticker in your passport instead of a stamp and writing on the sticker making it easier to read. The sticker is your visitors visa for the next month. Check the expiry dates as you don't want to be late for your stamp.