Do Medicare and Medical cover my parents while traveling?

The short answer is that Medicare will, but Medi-Cal won't, cover your parents when they're visiting you outside California. The longer answer is that Medicare is a national system, with consistent rules across all states, and is intended to protect people wherever they might be in the U.S. So, Medicare can cover your parents in any state, as long as they receive care from a Medicare-participating doctor or other health care provider. Be aware, though, that not every doctor or other provider accepts Medicare patients. Also, even doctors who take care of some Medicare beneficiaries might not be willing to take on new Medicare patients. So, if your parents visit you often, or for long stretches, it's probably a good idea for you, in advance, to find doctors who are willing to care for them. That way, you won't have to scramble for doctors if and when one of your parents actually needs care.

Medi-Cal (which is California's name for the Medicaid program), on the other hand, is specific to California and only covers California residents when they receive care from Medi-Cal participating doctors, hospitals and other providers within the state. Medi-Cal and other state Medicaid programs operate only in the particular state; they have reimbursement arrangements only with providers in that state. Medi-Cal covers the various costs Medicare does not cover, such as deductibles and copayments. So, in practical terms, if your parents get non-emergency medical care outside California they will be personally responsible for any costs Medicare does not pay. (If they receive emergency care, Medi-Cal will pay its share.)