Historically, a unified and reliable postal system (邮政, yóuzhèng) was crucial for governing the vast territory of China, connecting the capital with distant provinces. 邮寄 (yóujì) embodies this traditional, state-run system, represented today by China Post (中国邮政).
However, the most significant cultural context for a learner in modern China is the contrast between 邮寄 (yóujì) and 快递 (kuàidì).
邮寄 (yóujì): Associated with the standard, often slower, national postal service. It's still used for official documents, international standard mail, and sending things from more remote areas. It can sometimes feel a bit more formal or even dated compared to its modern counterpart.
快递 (kuàidì - “Express Delivery”): This refers to the vast, hyper-efficient network of private courier companies (like SF Express, JD Logistics, ZTO Express) that have exploded with the rise of e-commerce. For domestic package delivery, 快递 is the default in daily life. It's fast, cheap, and offers door-to-door service.
While in the West, “mailing” something can refer to both the standard post (like USPS) and private couriers (like FedEx/UPS), in China, there's a much sharper distinction in everyday language. Using 邮寄 when you mean a fast, modern courier might be understood, but it wouldn't be as precise as saying 快递.
You'll encounter 邮寄 in more formal or traditional contexts.
At the Post Office (邮局): This is the primary place where 邮寄 is the correct and expected verb. When you walk up to the counter with a package, you are there to 邮寄 it.
Official Forms: Government agencies or companies might ask you to 邮寄 documents or applications. Online forms might use 邮寄地址 (yóujì dìzhǐ) for “mailing address.”
International Mail: When sending a package or letter overseas through the standard postal system, 邮寄 is the appropriate term.
In casual conversation, if you're sending a friend a package domestically, you are far more likely to use 寄 (jì) on its own, or specify 快递 (kuàidì). For example, “I'll courier it to you” would be “我给你快递过去 (Wǒ gěi nǐ kuàidì guòqù).”