Poseidon for UML!

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

Lucidchart is an online diagram and flowchart software that supports Microsoft Office Visio import and can work on any operating system. The easiest way to draw flowcharts, wireframes, UML diagrams, network diagrams, mind maps, iPhone mockups, site maps and more. Work together in real time with your team and clients! Along with the online version, Lucidchart also has a downloadable solution that runs on Mac, Windows and Linux; this enables offline editing at any time! »

PlantUML is an open-source tool that uses simple textual descriptions to draw UML diagrams. The generator can be run anywhere within JVM and integrated with various application such as wiki, text editor, IDE, programming language, documentation generator, and others. Mostly based on Graphviz. Can render various diagram syntax such as PlantUML, Dot, and Ditaa.

Visual Paradigm for UML (VP-UML) is a UML design tool and UML CASE tool designed to aid software development. VP-UML supports key modeling standards such as Unified Modeling Language (UML) 2.4, SysML, ERD, DFD, BPMN 2.0, ArchiMate 2.0, etc. It supports software development teams in requirements capturing, software planning (use case analysis), code engineering, class modeling, data modeling, etc.

Umbrello UML Modeller is a Unified Modelling Language diagram programme for KDE. UML allows you to create diagrams of software and other systems in a standard format.

Enterprise Architect is a collaborative modeling, design and management platform based on UML and related standards. Agile, intuitive and extensible with fully integrated, powerful domain specific high-end features at a fraction of the cost of many competitors. An enterprise wide solution for visualizing, analyzing, modeling, testing and maintaining a wide range of systems, software, processes and architectures. Team based, with a proven track record and close to 200,000 users worldwide.

Lightweight, powerful, easy to use, UML tool

Graphical modelling open source UML2 tool based on Eclipse environment.

ProcessOn provides an easier way to create diagrams.It's completely FREE OF CHARGE .Drag and drop shapes, icons and other usuful elements in your logic thinking or following your procedure, then optimize your diagrams’ color, style,so everyone even the beginner will become a diagram rockstar just in a minute.ProcessOn also has a diagram library where you can choose tons of shapes and objects then share them through social network. Templates included:-Flowcharts-BPMN-Value chain-ERD-UML-UI/IOS mockups-Org charts-Venn diagrams-MindmapProcessOn is also a professional social network, specially designed for digrammers, designers, consultants, IT engineers.You just can connect with the experts or influences in your professional field, in the meantime, you can rise your personal reputation as well.Here you wont’ miss the lastest trends in one’s specific field.Now we support 5 languages. »

From free light-weight versions which provide Intuitive UML software at no cost; to the most powerful UML Plus software on the market Astah allows your team to communicate clearly and easily across platform. Take your Modeling to the next level with Astah.

NClass is a free tool to easily create UML class diagrams with full C# and Java language support. The user interface is designed to be simple and user-friendly for easy and fast development. Properties, enums, delegates and other language specific elements are fully supported with strict syntactical and semantical verification.

WhiteStarUML is a fork of StarUML with an intent to revive its Delphi code base by updating code to recent Delphi editions, reducing dependence on third party components and fixing bugs and adding new features.

UMLGraph allows the declarative specification and drawing of UML class and sequence diagrams. The current features are part of an ongoing effort aiming to provide support for all types UML diagrams.

System Designer uses UML, a standard, to define your model. So you probably already know how to create a model in System Designer even if you have never run it.