Zoro and Sanji's relationship was no secret. They might think it's a secret, but it's really not. The whole crew thinks they're being stupid for hiding something so obvious but doesn't say so because it's their decision and on the Going Merry, no one interferes with others' decisions.

Zoro and Sanji on the other hand thinks they're perfectly safe with the hidden relationship. They did try telling but the timing never seemed right as they were having one adventure after another and on the peaceful days, something would come up (like Sanji being pissed at Zoro and thus postponed the telling). They don't notice the crew noticing the change in their behavior.

There were signs all over the place, both of their relationship and the fact that everyone else knows. Zoro and Sanji were just too oblivious. They don't notice Robin smiling behind her book when there's a pause in the fight. They don't notice that Robin smirking when she heard the low moan from behind the mast. There's a pause and the shouting resumes.

Robin's the first to notice. She's the observer after all. Robin notices the way the two men sit slightly closer than nakama, much less nakama who don't get along. She arrives early into the kitchen and notices the way the cook prepares Zoro's with the amount of attention usually only reserved for the ladies. That's when she knows and smiles secretively behind the thick tome.

Nami noticed the change when Sanji stopped adoring her so excessively. He still does but it was somehow off, like he wasn't fully into it. It seemed more out of habit, the way someone knocks out of habit rather than actually needing to. She also noticed that Zoro and Sanji seemed to be closer and there were secretive (not really) touches here and there. This was when she realized that Zoro and Sanji were something more than just nakama.

Usopp was the third to realize. It was gradual and he had his suspicions. Most times when Sanji goes out to call Zoro in for dinner, they seem to take a tad longer than usual. Also, Sanji seemed more fluster, his clothes were rumpled and lips bruised. Zoro, however, is grinning. Usopp decides that they had a brief fight and Zoro won, nothing more.

But Usopp kept noticing that the time grew longer each time and both their lips looked bruised. Sanji would have a blush and sometimes his usual cigarette was out of place. Zoro would have a shit eating grin and tousled (more than so) hair. The last straw was when he actually stumbled upon them. Nami had sent him because they were taking way too long and when Usopp neared the crow nest, he could hear moaning. No shouts or curses, no sound of swords being sheathed or legs stomping. Moaning.

Usopp decided enough was enough and left. It didn't matter that his debt was raised or that Sanji and Zoro showed up to dinner 30 minutes late. He was way too busy trying to bleach the moaning from his mind.

Sanji doesn't notice Usopp blatantly checking the kitchen table in the morning (though like Sanji would do anything in his kitchen).

Chopper was the one who caught them in the act. It started with Sanji borrowing petroleum jelly from the infirmary. Later that day, Chopper went out to search for the gel. He scoured the ship for Sanji and finally found him with Zoro in the men's bunk room…kissing. Chopper had freaked out and trying to be as silent as possible, snuck out of the room, scampering to the deck. As he lay panting, he fully realized just what Sanji and Zoro were doing. Or about to do.

Chopper knew about sex, of course, He was a doctor. Of course he knew how babies were made (though he spent around two months trying to deny and erase what he'd learned until Dr. Kureha conked him on the head and yelled at him for being immature). What Chopper didn't understand was how two men could do it.

Chopper went to Usopp. Usopp would know, he thought. But when he asked about it, the sharpshooter ran away screaming 'Brain bleach! Brain bleach!'

He thought of his options. Nami was scary and Luffy… did he even know about intercourse? And more importantly, did he know how men do it?

Robin!

Robin would know. He could ask Robin.

Chopper found Robin sitting next to Nami on the lawn chairs and tried to discreetly ask her.

"Oh my, why would you know something like this, Doctor-san?" Robin asked in a amused tone.

Nami overheard. "Chopper, I can tell you all about it but you have to pay be 2000 beri, ok?"

"Wahh! I don't have that money!"

"1500, then?"

"I still don't have the money!"

"Oh, stop teasing, Navigator-san. Come here." Robin whispered into Chopper's ear.

"EH? They do that?! But… EH?..."

Chopper refuses to meet Sanji's eyes when he came to return the gel, insisting that the blonde keep it and it was almost gone anyways (it was barely used). Chopper stutteringly refused Zoro's offer to trade veggies at dinner.

When Zoro and Sanji finally thought of telling them, the rest of the crew didn't know how to respond. It would be terribly rude to tell them that they already knew because it was obvious that they were nervous and worked up courage to do it. Well, Sanji looked nervous about the girls' reactions (the men's can just be thrown overboard) while Zoro couldn't care less.

They all looked at each other, unsure of what to say. Luffy decided to be blunt. "We already know, though."

"WHAT?"

"See, curly-brows? It's not that big of a deal."

"You stupid marimo!" Sanji whacked Zoro on the head. "Of course it's a big deal! How did you guys know?"

…

"Wait, did you tell them before? I thought we were going to tell them together!"

"OI! I didn't!" Zoro protested loudly at the mention of him breaking a promise.

"Um.. Sanji-kun, we just found out on our own. You guys weren't really that discreet," Nami tried to soften the blow.

"Yes, cook-san. You pay a lot attention to food arrangements, don't you?" Robin smiled.

"Brain bleach, brain bleach, brain bleach," Usopp muttered as a mantra. One could guess how he found out. That would also explain why he was avoiding them so much.

Chopper looked at the couple like they were aliens. He dazedly whispered, "Petroleum gel…" Nami chuckled, immediately getting it. Zoro raised an eyebrow to Chopper in surprise.

"Of course, Nami-swan and Robin-chwan would figure it out! They're so smart!" Sanji twirled around the room, managing to avoid all the sharp corners and bodies in the crowded room. "And you lot! You should just go to hell, wasting all my hard work."

"It's not that big of a deal. You worried about nothing, ero-cook," Zoro chastised, chugging down more sake.

"It's a huge deal! What if the ladies didn't like bisexuals?" Sanji protested.

"Tch. Like they have a say in this. What if the guys didn't like bisexuals?" Zoro returned.

"They'll deal with it," Sanji flippantly waved his hand.

"So, Luffy. How did you find out?"

"Eh?" Luffy looked up from his meal, cheeks bulging out with meat. He swallowed. "Oh, it was obvious."

"How so, captain-san?"

"Eh? Santoryuu," Luffy pointed his meat bone at Zoro. "Curly-brows." He pointed at Sanji and looked at the rest of the crew like it was just so obvious.

Nami promptly punched him on the head. "Idiot! Those aren't even reasons!" Chopper and Usopp nodded in agreement.

"Ah, captain-san's logic," Robin smiled mysteriously like everything made sense.

I'm so productive today! Updated two of my stories and made a new one!

I had this one for quite some time but finally finished editing it. Just a short little one shot, mostly centered on how the crew (before Water 7) found out and I really just wanted Luffy's last comment in the end. Robin's also quite awesome to write, though she doesn't do much. Plus, we all know how much Zoro and Sanji would suck at hiding their relationship.

Anyways, I hoped you liked it.