Honestly, it was pretty bad. I don't know if it's just a carrier issue (we have Sprint) or if it's just bad all together. We had low speeds (3 dots of 3G, if we were lucky) and often had times with absolutely no service. We found it was worse in California Adventure one day, especially in the Paradise Pier area. Another day, we had decent service there. We hardly ever had 4G/LTE service. It was really bizarre to have such poor service in such a populated area.