Yes, you can learn Dutch as a third language even if you never visit a Dutch speaking country, but your decision should depend on your personal motivation and goals. German and Turkish each offer different trade offs in terms of speaker base, linguistic difficulty, and cultural access.
First, assess your primary reason for learning. If it is pure interest in Dutch culture, literature, or history, then Dutch is a rewarding choice. It is one of the easiest languages for English speakers due to shared vocabulary and grammar, and there is a wealth of online resources, music, and media. However, with about 24 million native speakers mostly concentrated in the Netherlands and Belgium, you will have limited opportunities to use it in daily life unless you actively seek out online communities or texts. Without immersion, reaching high proficiency may require extra effort to maintain speaking and listening skills.
German, in contrast, has around 95 million native speakers and is widely used in central Europe. It opens doors to a larger job market, more academic literature, and travel opportunities even if you never live there. The grammar is more complex (three genders, case system) but still manageable for a third language learner. If career growth or broad European travel appeal to you, German might give you more practical return.
Turkish has about 80 million speakers and is a non Indo European language, meaning it is grammatically very different from English and Dutch. That can be a stimulating intellectual challenge and offers deep access to Turkish culture and a large diaspora. It is less widely taught but growing in popularity. If you are motivated by a specific connection to Turkish culture, family, or future travel to Turkey, it could be a strong choice.
No language is a bad decision for a motivated learner. The real question is what will keep you engaged over months and years. You can start with free apps like Duolingo or Memrise to sample each. After two weeks, you will have a clearer sense of which one feels more natural or more exciting. If you choose Dutch, lean into the large amount of subtitled Dutch TV shows (many on YouTube) and join online speak clubs. Consistency beats intensity. Remember that learning any third language makes learning a fourth easier, so there is no wrong choice. Choose the one whose culture or content you genuinely want to connect with.
Finally, do not worry too much about practical necessity. Many people learn languages purely for mental exercise or personal satisfaction. Dutch Fluency is achievable with consistent practice, especially if you enjoy the process.