The Rules:  

Before, I used to dismiss the idea of time travel in
Hetalia. Looking back, I can see that this limited my understanding of several
bizarre and inexplicable occurrences in the manga.

In a fictional series
where the nations are immortal, being referred to as “strange” and “odd”
beings, it’s honestly not that far-fetched to consider that they’re capable of
time travel.

This is especially true given the facts that…

1)  Time is experienced differently by the nations.

Ex: Canada spends an entire weekend staring at Kumajiro’s
eyelashes. It passes by without him realizing this [x].

Ex: If a human were to spend enough time around a nation,
their perception of time would become so warped that they’d go mad.

Ex: Pets don’t go mad when they’re around their nation
owners. Instead, their lifespans increase. Should they separate from the
nation, however, they would become normal pets again and resume aging [x]. 

2)  Some nations are capable of magic,
fortune-telling, clairvoyance and other supernatural abilities.

Ex: England’s and Romania’s ability to cast spells.

Ex: Japan’s powers of clairvoyance and mind-reading [x]– I’ll
get back to this later.

Evidence of time travel in Hetalia is either extremely
subtle or so right in your face that it’s easy to overlook.

Could it be that the pets don’t age because the nations are beings that are able to transcend space and time? In other
words, what if time is bent around the nations, which, in turn, causes their
pets not to age?

They’re timeless beings in that they’re immortal. While they
do age, it’s very incremental. They still remain youthful, likely because time
is slowed for them. In that case, the reason that the pets won’t go mad by
being around a nation is that they don’t perceive time the same way that humans
are able to.

Are the nations able to time travel then?

Evidence from the manga suggests that they’re indeed able
to.

Let’s go over some of these examples.

Bizarre and Casual Anachronisms: 

If you factor in time travel, this would explain the sudden
appearance of anachronisms when you least expect it. I used to think that these
were silly comic gags. My opinion has since changed.

Ex: When America pulls out a computer to google where
Germany is in 1942, England isn’t surprised. Instead, he’s able to pinpoint
exactly how far into the future the model is and reprimands America for showing
off.

Ex: Why is it that during the 18^th century, Japan
appears to be listening to music…with earbuds? [x].

Ex: The Roman Emperor Nero is once depicted to be playing an
acoustic guitar.

They’re aware that it’s an
anachronism. Perhaps either Rome or Quintillus – another Roman Emperor who’s
canonically able to time travel – brought that there. I’ll get back to
Quintillus in a moment.

Japan’s Powers of Clairvoyance: 

As mentioned above, Japan has been shown to be able to read
minds, see into the future, and establish contact with others without having
ever met them in person before.

Ex: Japan demonstrates his clairvoyant powers during the
Meiji Era. The fourth wall is broken as the scene pans in on
Himaruya scrambling to finish a comic.

Ex: When Japan first becomes acquainted with the Italy
brothers, they’re put off by how silent and reserved he is. Japan later admits
that he’s not used to speaking out loud with those whom he’s read the minds of [x].

If anything, this alludes to the fact that Italy and Japan
have technically met before.

Notice the title of the strip too. “A melody that transcends
history and reaches you…”

Japan’s ESP Contact with Italy + Dream Sequences:

After falling into bed with Holy Rome, Chibitalia has a
strange dream where he encounters a presumably divine being that leads him to –
yes, Japan. This confirms what Japan claims in World Stars. He did, in fact,
read the mind of Italy and communicated with him far before they formed their
alliance in WW2 [x].

That’s not it, either.

Italy in adulthood has a ‘unpleasant dream’ of a child that looks
exactly like him pressing to be acknowledged [x] [x].

How I’ve interpreted this before is that it symbolically
represents Italy’s unconscious mind repressing memories from his childhood. Put
another way, he’s refusing to remember – acknowledge – bits of his past.

Taken literally, this could also mean that Italy’s child
self is transcending time and space to get him to remember his past.

Or, what about this scene? Italy encounters his child self, recognizes this, and feels ashamed for
lying about how [not] strong he’s become [x]. 

Germany also appears to have these strange encounters with chibis.

Ex: In the same strip, a child that looks
exactly like Germany/ Holy Rome presses to be acknowledged as well [x].

Ex: Germany’s once shown to be holding up Chibitalia.

“It’s me!”

What if this is Chibitalia traveling into the future
to get Germany to remember about his past as Holy Rome? At the same time, it could symbolically represent childhood memory repression. Of course, this is all making the assumption that Germany is, in fact, Holy Rome.

Quintillus:

Most obvious of all is that there’s a real character in the series
who’s physically able to time travel.

The play on Quintillus’ time-traveling abilities is that
because historical records about him are shifty, his timeline leaps back and forth.
Himaruya took this, made it literal, and gave Quintillus time-traveling powers [x].

Ex: We see Quintillus visit Germany in modern times making
sure that the latter’s research and re-writing of Roman history are accurate [x].

With all the evidence I presented, I truly do believe that
the nations are able to time travel. It’s not just limited to their ability to
slow time for those around them. They seem to be able to manipulate it too, being able to disappear on
a whim…