For most circumstances, yes. Consider looking into some sort of Voice over IP method that would allow you to call the US over the internet for free or at much lower rates than conventional landline.
However, with you having Hokuto in your name, if you're in Japan, there MIGHT be a call center for you - Japan and North America appear to have the only two large sets of permanent UO staff (Europe & Oceania go through the US; not sure how customer service is handled for the ROC & ROK). Check the Japanese UO official site to see if you can find a contact phone number for customer service. There is the matter, though, that all shards log in through a server in the US, even if the shard itself is located in the Eastern Hemisphere, which is why I'm unsure if the Japanese UO staff can help.