Argthtjtr

I live in the USA on a green card. My dad's retired and my mom had a year off of work (until Sept). We are all Canadian citizens.

I just had a kid, and they wanted to come and visit and stay with me until the end of August to be grandparents. I know as Canadians you get 182 days without needing a Visa, but I'm having trouble finding what their options are beyond this (i.e. to stay 8 months instead of the 6). In the worst case of course they can go back early. I'm thinking that we'd need to apply for a B2 visa, but I haven't found a concrete answer

Something to think about is the length of time they'll be gone from Canada.

Most provinces you must spend a minimum of six months in a twelve month period in that province to be counted as a resident. After that you generally lose benefits such as health insurance and must go through a three month repatriation period before you're covered again. Quebec allows an exception to this once every seven years but it must be applied for, I'm not sure if any other provinces have such rules. See here for more information.

"182 days without needing a visa" is not correct. Canadians are admitted for six months without a visa, as if they had a B-1 or B-2 visa (depending on the purpose of their trip). The 182-day limit that Canadians often talk about derives from US income tax law, not immigration law. If your parents spend a sufficient amount of time in the US, they will become "resident aliens" for the purpose of tax law, which will mean that they are required to report and be taxed on their worldwide income. This is based on their physical presence in the US, so it has nothing to do with immigration status.

The six-month limit in US immigration law is usually six months per visit. It's also just a default, which cannot be reduced without a good reason and approval from a supervisor. A border officer can actually admit them for up to one year if they ask for it when they enter. I have no idea whether that is a good idea, however; it might increase the chance of the border officer refusing entry.

Another option is to file an application for extension of status after they arrive in the US. This is a bit pricy, however, at $370 per person.

Applying for a B-2 visa would not change any of this; they'll be admitted as B-2 visitors regardless of whether they have a B-2 visa.

I'm not sure what's going on with Canadians and I-94s these days. It used to be that Canadians entering by land didn't get an I-94, but I think that may have changed. They should check at https://i94.cbp.dhs.gov after they arrive. If they do get an I-94, they should be aware that a trip to Canada and back might not reset their period of admission, as they can be readmitted on the same I-94.