If you think Sam Heughan is not the kind of guy who would wear a bright gold temporary tattoo celebrating the show he works on, you are wrong about the “Outlander” star.

In a hotel near the San Diego Comic-Con convention center — where the cast and producers were treated to a rock-star reception in July — Hueghan arrives at a post-panel interview sporting an “Outlander” tattoo on one bicep. And though his co-stars Caitriona Balfe and Tobias Menzies are not similarly decorated, they are just as game to talk about the past and future of “Outlander,” which returns with its third season Sunday on Starz.

If there’s one thing that’s clear about all three actors, it’s that they take their responsibility to the show and its fans seriously. They’re all quite happy to mock themselves — at one point, there’s a long conversational segue about how Sam would happily wear down Tobias’ superior tennis skills through the deployment of stubborn, unskilled doggedness.

But all three grow contemplative and thoughtful when asked about the complicated lives of the people they play. Over the past two seasons of the show, it’s become obvious that they’ve all worked hard to make the emotional bonds among their characters meaningful and even a little unpredictable.

As the third season gets underway, Claire (Caitriona Balfe) must contend with what she thinks is a final separation from her 18th Century husband, Scottish Highlander Jamie Fraser (Heughan). In mid-20th Century Boston, Claire gives birth to Jamie’s daughter, Brianna, and forges a new life in a sometimes unwelcoming medical community. Still, her career thrives more than her challenging relationship with Frank (Tobias Menzies), who can never quite be sure where his wife’s mind is — in the past with her Scottish husband, or in the present, with the man she married well before she ever met Jamie. (Menzies also plays Jamie’s nemesis, Black Jack Randall, with whom Jamie has a memorable encounter in the Season Three premiere.)

That first episode of the season sets a lot of new storylines in motion and closes off others. But that’s one of the themes of “Outlander” — that change is inevitable and it’s sometimes quite drastic.

If you could travel in time, back to the day before filming on “Outlander” began, what advice would you give yourself?

Balfe: Get sleep.

Heughan: Yeah, me too.

Balfe: You’re never going to sleep again. [Laughs.] Is it cheesy to say, “Trust your instincts”?

Heughan: I feel like I wouldn’t tell myself anything. I know it sounds cheesy, but this has been such a journey. Four years now. [Heughan’s casting was announced July 9, 2013.]

Balfe: I also think our blindness and naivete helped us.

Heughan: Yeah, we’ve all grown up with the show. Our lives have changed with it, and it’s definitely been very rewarding and informative. But sleep is definitely [a priority].

Menzies: I guess I would probably tell myself, maybe, “Enjoy the ride a bit more.” I suppose that’s [the best advice] for everything, isn’t it? Worry less, just enjoy it. But you can get caught up — you want it to be the best show that’s ever been made. I think we all came into it really passionate for it to be as good as it could be. And I think that has actually paid off. Because I think we had lots of people really demanding a lot of it.

It sounds like a lot of pressure.

Menzies: Pressure that we were putting on ourselves.

Balfe: I think we all fight really hard for what we believe in, for what we think will elevate things, and I think that goes across the board. Everyone tries to make sure that everyone’s working at their A game…

Menzies: …because, look, this could be an incredibly different show. Just tonally. I’m very proud of what we’ve made, and where it is tonally.

It does all hang together, but does it ever feel sometimes like you’re making a series of different movies? There are battles, a variety of time frames, and locations that go from Versailles to the Scottish countryside to Boston in the 20th Century.

Heughan: I think for the designers and the costuming, each season does feel like an entirely new show. They often talk about that. In Season Two, they had to envision France. This season, the second half is in Jamaica. Am I allowed to say that?

Balfe: Yeah. It’s Boston and then Jamaica.

Heughan: So it’s not a show where you just go back to the same set. It’s just, clean slate — start again. It is like a new show each time.

Menzies: I think this season even more than the others [it moves around]. But it always had that. Every episode does feel different. In Season One, it was set in a castle. It was also in the 1940s. And then it was on the road [in Scotland]. It’s always moving. It’s always, “What are the challenges for this episode?” This season, Episode Four — to me, it feels like “Downton Abbey.” It’s set on this estate. And then suddenly, we’re in Edinburgh. We’re very lucky with the show. We’re not stuck in a studio the whole time, in the same sets doing the same thing. There’s always a new challenge.

Is it a bit disorienting at times? Do you miss the rhythms or the rapport that you had with the people that you worked with regularly?

Balfe: Yes. This season I think more than any one before. Towards the later part of the season, we work with these completely new groups of people. And [Sam] and I, a couple of times, we are not in the same episode. In the beginning of Season Three, it wasn’t such a change for me, because we started Season One with Claire and Frank. We started Season Two with Claire and Frank [as is the case with Season Three]. So it didn’t feel that different. And even though the landscape and the settings always change, our characters always have [an ongoing] through-line. And that’s the grounding thing about this show. It’s what makes it not so disorientating, as an actor.

But definitely, what is a big challenge is when you’re doing different time frames. So, if you’re playing something from the 1940s and 1950s, and you go back and play something from the 1960s, you’re just trying to keep a consistent line of where your character is, in terms of their life, and things that you want to add if they’re a bit older or younger.

Heughan: That was a whole new challenge of this season — a lot of aging goes on.

Balfe: Quickly, too.

Menzies: Also, there was a real bond in Season One between the cast. [Saying goodbye to actors whose characters first appeared in the first season] — for me and I think for most people in the crew, it was about losing that world.

Balfe: In Season One, it was new for all of us. We had all started on this journey together. It was so fresh, and that bond you’ll never really get again.

Sam, one of the new modes for your character this season is Caveman Jamie. The fans are going to love Feral Jamie. Seriously, though, Jamie’s arc at one point near the start of the third season is quite sad. Is he just paralyzed by grief?

Heughan: Yeah. At first, he’s just out of the battle [of Culloden]. He’s alive and in pain. And he’s lost Claire. In the second episode, I wanted him to be almost frozen in that pain. He’s almost just dead to the world. It’s just a state of shock.

Menzies: I remember you fighting for that. I remember you having conversations with the writers like, “I can’t recover from this too easily.” I was watching the episode last night, and that paid off so well. He really changed. There’s a weird silence around him.

Heughan: Yeah. Actually, it’s funny, you always watch these scenes back and you go, “I wish …” [That version of Jamie] had so much hair that you can’t quite see my eyes, and I think sometimes you lose what’s going on there. But he is lost in his pain and [has visions of Claire]. In fact, there is a moment when he does see her. And I think he believes that is happening all the time — that he’s seeing her. By Episode Three, he’s living in the memory of her. He’s happy to dwell in the shadows, and just be lost in the memories of someone he loved in a happier time. He doesn’t want to face the reality of the world, so he’s fine to be [psychologically] imprisoned.

Caitriona, even after Claire arrives in Boston with Frank, do you think she always thought about going back to Jamie? To try to find a way?

Balfe: I don’t think she thinks he survived. I think that she 100 percent believes he’s died. Everything she’s read about the battle of Culloden, everything that she’s heard about it, is that the Highlanders were decimated. That nobody survived. And I think she knows Jamie so well that she believes that he would fight to death.

Heughan: He wouldn’t leave his men behind.

Balfe: I think if she had any inkling that he might have survived, it would have been harder for her to even attempt to forge a new life with Frank. So she’s a widow, then, and for the sake of her daughter, she has to try and forge a new life. Women have that resilience. Claire is a survivor, and you will do anything for your child. So I think that that’s the only way she was able to shelve that memory of Jamie, in a way. Not that he ever leaves her, or leaves her thoughts — it’s not that. But I think if she thought that he was alive, and that there was a chance to go back, this life wouldn’t have been possible.

Heughan: It is a death for both, isn’t it?

Balfe: Yeah. That’s what I really wanted to play with. How do people move on after they’ve lost the love of their life? It’s a really interesting thing to look at. It happens to people every day, you see people … even in the worst, most war-torn places, people get up and continue with their lives. And it’s a fascinating thing about human nature. That ability to just continue on. It’s amazing.

Menzies: And also, in the first episode back, you have a birth at the heart of it. And that is the purest expression of renewal.

Heughan: She just needs to hope.

Balfe: [The child] is a part of Jamie. And that’s what makes the relationship between Brianna and Claire so complicated. In a weird way, Frank and Bri have the strongest bond, because for Claire it’s got all of these complications. She’s a constant reminder of Jamie, without being allowed to celebrate that, or acknowledge that in any way. So it becomes this very fraught, internal dilemma. Especially for someone like Claire, who is so passionate. Even before Jamie, with Frank, her sexuality and all of that was such a huge part of who she was. And after [going to Boston], that’s a side of her that she just shelved and put aside. It’s tragic. You see the two of them in separate beds, that kind of thing.

Heughan: It’s sad.

Balfe: It is.

Menzies: [The Boston storyline] also has some modern complications — the idea of a mother who isn’t entirely at home being a mother to that daughter.

Balfe: Yeah. In the book there are such great scenes where you see more of the struggling working mother. Given the time restrictions [of a season of TV], you really don’t see much of Claire [in that mode]. You see that one scene of her first day in college and how condescending the professor is. You just know from that how tough that journey for her is, and what battles she has to fight to become a doctor in that time.

So much of the show is about Claire or Jamie finding a situation — or being put in a situation — they can’t tolerate, and then fighting the unfair status quo.

Balfe: But I think Claire also has a calling. That’s her drive. Some people are just born to do the thing that they do. And she’s born to be a healer. And no matter where she is, she finds a way to make that happen. When she meets Frank’s colleagues, and the Dean puts her down and puts down the whole notion of female students, and female medical students — that’s the day she decided, “F–k you, I’m going to become a doctor.”

Heughan: What’s funny is Jamie actually never wanted to be involved in any of this. He never wanted to be part of the Jacobites, he just wanted an easy life. He wanted to be with his wife. It’s just fate, and history has just forced him to this point. When we meet him again [when he’s older], he’s printing seditious material. He is a rebel again. He just wanted to go home to Lallybroch. But history has forced him into that situation.

Menzies: He’s not driven by ego, is he?

Heughan: No.

Check back next week for an in-depth interview with “Outlander” executive producer Ronald D. Moore.