Many Viking tattoo designs today hold negative connotations because they were chosen by white supremacists to represent their cause. This is due to the conquering nature of the Vikings, and the fact that white supremacist groups in Europe could trace some of their history back to these people. In Viking culture there was nothing hateful about the swastika or any of their symbols, many of them were simply representations of their God Odin.
The benefit of choosing to place just a Viking symbol as a tattoo is that they are normally simple and bold designs. This means that they can be done relatively small and therefore placed nearly anywhere on the body. Viking symbols are nearly always done in solid black. The negative effect of choosing the symbol is that this are sometimes misunderstood to be racist because many white supremacist groups have adopted Viking symbols to their cause, even though historically these symbols had no relation to white supremacy.