You might want to include the time it takes and the profit per unit per trip...

If I had a nickel for every time someone told me that my idea for melting down coins to make a giant robotic parrot was a bad idea, I would have one kicka$$ giant robotic parrot.

Ruiz Base in omnicron beta to planet manhattan with Cardamine about £1300-£1500 per unit

The Niobium/Diamond runs are the best I think, between New Berlin/New Tokyo.
Ofcos, I'm saying this cos I am neutral to everyone. After sometime, you'll get bored cos it's just plain shipping...no pirates to hamper you nor any of the attacks you get when you come out of jump hole.

could you tell me the jumpholes you use to make that run quick? i ask because i dont know which ones to take so i end up going the long way round.

I have a pretty good one, most likely nothing will be hostile for the majority of the trading. It involves having atleast neutral (better to be friendly) repuation with GC, which most people are.

If your hanging around Bretonia, which I am pretty close to since I like to use the Dromedary use the whole trade route.

Planet New London with Luxury Food -> Planet Manhatten, NY
Planet Manhatten with Luxury Goods -> Ainu Depot, Hokkaido (GC)
Ainu Depot, Hokkaido with Cardamine -> Roppongi Station, Tokyo
Roppongi Station with Luxury Goods -> Ainu Depot, Hokkiado
Repeat steps 3 and 4 aslong as you like, its a pretty fast and safe trip

I like to bribe GC so they dont get confused and ask for the cargo back.

"It is said that revenge is a dish best served cold, it is very cold in space."
~Khan, Star Trek II: The Wrath of Khan

A good low risk one is:

Planet Denver, Colorado -> Planet New Tokyo, New Tokyo (Lux. goods)
Planet New Tokyo, New Tokyo -> Planet Denver, Colorado (Eng. Comps)

This is pretty safe if you take the long route, through Kepler and Shi***u but quicker through Galileo to Shi***u.

2way its about $1200 per unit

If you die you only lose about $50000 in a dromedary but you can gain $33000 in a 2 way trip.

The best trade by far is:

Cardamine from Yanagi Depot (Sigma-13) to Planet New berlin (New Berlin), And engine components on the way back Really short trip, less than 5 mins for a round trip!

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WARNING: THIS POST MAY CONTAIN TRACES OF PEANUT

I'm still a newb but I've tried most of the ones mentioned here and the New Berlin <-> Yanagi with Eng. Comps and Cardamine is definitely the quickest money I've made...and easy if you're neutral with most factions. And even if the cops catch you, you usually can dock with the tradelane or ring before they finish asking you to drop the 'mine.

My 2 senses.

I skipped Frankfurt by using the jump hole at Sigma 13, but to use this jump hole, you need to have a good relation with the Junkers, cos of Yanagi base is just beside that jump hole.

New Tokyo -> Honshu -> Sigma 13 -> New Berlin
and vice versa for return trip. The Sigma 13 hole is pretty good, cos coming out from it into New Berlin, puts you very near a trade lane heading straight to Planet New Berlin.

Happy Trading!

I ran Lux. Goods from Manhattan to Ainu and then Cardamine for the return trip, very profitable, but it sounds like the Ainu > Roppongi run is about ten times quicker. Not to mention safer, given my neutral rep up in Kusari space.

Light arms from Detroit Munitions ($124?) to Planet Crete ($1400?) and back with Artifacts from Crete ($188?) to Manhattan ($1200?).

Or, for a quicker and safer route...

Luxury Conxumer Goods from Manhattan ($180) to Planet New Tokyo ($990?) and back with Engine Component ($225?) to Denver ($825) and then H-Fuel to Manhattan just so you don't go back empty.

Quickest/Safest route possible...

H-Fuel from Ft. Bush ($330) to Baltimore Shipyard ($360) don't even have to steer, just target them in the contact list and hit F3 to dock, they're right next to each other. Profit bites, but it's a great way to kill time when you're waiting for a friend to show up in the NY system. Figure in a Rhino you'll make $2400 per trip, that's more than most missions in the system

By the way, I used to like a route from Manhattan to Cambridge and back, running LCG and LFood back, but now I think it's the worst route possible. I must've been lucky at first, because the last two times I attempted it, I lost half of the food waiting at jump gates.

A good one is engine components from planet honshu ($150) to planet malta ($1350) in the Omicron Alpha system. That's 3 system jumps with no one firing at you if you've bribed to get friendly with the outcasts (you can find that in the bar at freeport 6 in tau-29).
Unfortunately there is no return trade that is profitable, but my friend does a more lenghty trade route that pulls in a reasonable amount fairly quickly.
It goes as follows:

*Honshu: Engine Components ($150) -> Malta: ($1350) -- Profit ($1200/4 gate jumps)

*Malta: Oxygen ($30) -> Ruiz Base: ($60) -- Profit ($30/1 gate jump)

*Ruiz Base: Alien Organisms ($100) -> Shinjuku Station: ($1100) -- Profit ($1000/9 gate jumps minus $100 times 6 to 8 organisms that perish)

*Run form shinjuku to New tokyo or Roppongi station empty (1 gate jump).
Buy Luxury Consumer goods ($810) -> Honshu ($990) -- Profit ($180/5 gate jumps)

That's $2410 profit per unit and a total of 20 gate jumps across 4 systems.
Sounds like a lot, but it isn't really, and your most profitable runs are on the longer routes.

I'm sure there are better trade routes around, but this one netted my friend about 4 mill in 2 hours which is not to be sneezed at (It took that long because I was badgering him to look around a bit).

Anyway, Happy Hunting

My best and easiest is the return trade route of Planet Cambridge (Luxury Food) to Planet Denver, then Denver (Optronics) to Planet Cambridge, even though you might lose 5 to 10 unit of luxury food the nett gain is about 2,300 credits per unit per round trip. Pirates are softies on the whole of this route, so take them out when you're carrying going to Cambridge and run for it when going to Denver. Easy money

Here's hoping for reincarnation!