Is betting on sports online legal? I have read it is, I have read it is not. What’s the real story?
I’ll lay you 8-to-5 that it is. 
Seriously, that’s a question for your local jurisdiction. Check with them.
Seems like they are all based “offshore”.
Most of the gambling operations are based outside the United States, but that’s primarily to make them difficult to prosecute. It doesn’t make their activity legal when performed in the United States. Note that I express no opinion on whether said activities (I love saying “said” when talking law) are in fact illegal.
I think this topic is what legal scholars would describe as a “gray area”
Depends on state law.Nevada it’s a nono,among others.
Recognize also there’s no gaming comission to notify if they take the money and run Venezuela.
As **Spoons ** said,check with the local gummint.
And if you’re cleared and you’re betting sports,I’d stick with a UK site like Ladbroke’s if they have one.They’ve been doing this stuff for years legally before the internet was ever invented by Al Gore.
Some small town bookies moved to Costa Rica or the Bahamas back when this was starting to take off and more than a few of them went bellyup ala Larson at the old Rose Bowl.
FTR, when the Internet first became big I was living in Missouri. The Missouri Attorney General at the time, Jay Nixon, was something of a nanny and decreed that online gambling in Missouri was illegal.
So one night I went to the library and tried to log on to an offshore gambling site, and whaddyaknow? I got a message that said, to this effect: “We have detected that you are attempting to log on from a location where this activity is illegal. Sorry.” Their server must have detected that I was logging on from a Missouri server and thus re-directed me.
A few weeks back they did a report on 60 Minutes (maybe Dateline), regarding this. The guys who ran this are off shore and when one of them returned he was arrested and prosecuted. You may want to check sites for 60 Minutes to see if there is info there.