Is international roaming free in Ecuador with my existing US, Canadian, or European SIM card?

No, definitely not. Ecuador is not part of any domestic roaming agreements for most North American or European carriers. If you use your home SIM card, your provider (like AT&T, Rogers, or Vodafone) will likely charge you their highest international roaming rates, which can be very expensive—often $10-15 per day or more for limited data. An Ecuador Abroad eSIM offers a far more economical and transparent solution, providing dedicated local data at a fraction of the cost, so you can explore Quito or the Galápagos without bill shock.