Can you switch Medicare supplemental plans at any time?

It depends on which supplement plan you are talking about. If you are talking about part d drug coverage then no you have to make changes during open enrollment. If you are taking about your part C your healthcare coverage, then in many cases the answer is yes you can change mid year or anytime. We were looking to change my mother's a few years back and they allowed it in April.

Sorry for confusion in my reply. Open enrollment is correct time to switch.

You can't change plans at any time. You're going to have to wait till the yearly open enrollment period.

Yes marci1026 is correct. Medigap plans (i.e Plan F) can be changed anytime but medicare advantage & part D drug plans can only be changed at open enrollment beginning in October or if you move out of your service area.

I do think that you can change supplemental insurance anytime. Best to check with a supplemental plan. Premiums may be higher. You need to wait for open enrollment to change primary Medicare or Medicare advantage.

No, only if you move out of the network, or lose existing coverage for some reason. Otherwise you use the open enrollment period, which just closed.